diff --git a/.github/workflows/gh-actions.yml b/.github/workflows/gh-actions.yml
index c984c28036..4a7d5bf8eb 100644
--- a/.github/workflows/gh-actions.yml
+++ b/.github/workflows/gh-actions.yml
@@ -256,8 +256,8 @@ jobs:
       - run: sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa
       - run: sudo apt update
       - run: sudo apt install gcc-arm-embedded python3-setuptools
-      - run: make -f ./targets/mbedos5/Makefile.travis install
-      - run: make -f ./targets/mbedos5/Makefile.travis script
+      - run: make -f ./targets/os/mbedos5/Makefile.travis install
+      - run: make -f ./targets/os/mbedos5/Makefile.travis script
 
   Zephyr_STM32F4_Build_Test:
     runs-on: ubuntu-latest
@@ -268,8 +268,8 @@ jobs:
           python-version: '3.x'
       - run: sudo apt update
       - run: sudo apt install gperf dfu-util device-tree-compiler
-      - run: make -f ./targets/zephyr/Makefile.travis install
-      - run: make -f ./targets/zephyr/Makefile.travis script
+      - run: make -f ./targets/os/zephyr/Makefile.travis install
+      - run: make -f ./targets/os/zephyr/Makefile.travis script
 
   NuttX_STM32F4_Build_Test:
     runs-on: ubuntu-latest
@@ -277,8 +277,8 @@ jobs:
       - uses: actions/checkout@v2
       - run: sudo apt update
       - run: sudo apt install gcc-arm-none-eabi libnewlib-arm-none-eabi gperf
-      - run: make -f ./targets/nuttx-stm32f4/Makefile.travis install-noapt
-      - run: make -f ./targets/nuttx-stm32f4/Makefile.travis script
+      - run: make -f ./targets/os/nuttx/Makefile.travis install-noapt
+      - run: make -f ./targets/os/nuttx/Makefile.travis script
 
   RIOT_STM32F4_Build_Test:
     runs-on: ubuntu-18.04 # needed due to ppa:team-gcc-arm-embedded/ppa
@@ -289,8 +289,8 @@ jobs:
       - run: sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa
       - run: sudo apt update
       - run: sudo apt install clang gcc-arm-embedded gcc-multilib
-      - run: make -f ./targets/riot-stm32f4/Makefile.travis install-noapt
-      - run: make -f ./targets/riot-stm32f4/Makefile.travis script
+      - run: make -f ./targets/os/riot/Makefile.travis install-noapt
+      - run: make -f ./targets/os/riot/Makefile.travis script
 
   ESP8266_Build_Test:
     runs-on: ubuntu-latest
@@ -299,8 +299,8 @@ jobs:
       - uses: actions/setup-python@v2
         with:
           python-version: '2.7' # needed due to ESP8266_RTOS_SDK/tools/gen_appbin.py
-      - run: make -f ./targets/esp8266/Makefile.travis install-noapt
-      - run: make -f ./targets/esp8266/Makefile.travis script
+      - run: make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis install-noapt
+      - run: make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis script
 
   Notification:
     runs-on: ubuntu-latest
diff --git a/targets/curie_bsp/README.md b/targets/baremetal-sdk/curie-bsp/README.md
similarity index 96%
rename from targets/curie_bsp/README.md
rename to targets/baremetal-sdk/curie-bsp/README.md
index 967782a754..051e5f0ab0 100644
--- a/targets/curie_bsp/README.md
+++ b/targets/baremetal-sdk/curie-bsp/README.md
@@ -62,7 +62,7 @@ You will first register in the web page. Then you will receive an email where is
 
 #### 3. Build JerryScript and Curie BSP
 ##### 1. Generate makefiles
-Run the Python script ``setup.py`` in ``jerryscript/targets/curie_bsp/`` with the full path or relative path of the ``Curie_BSP``:
+Run the Python script ``setup.py`` in ``jerryscript/targets/baremetal-sdk/curie-bsp/`` with the full path or relative path of the ``Curie_BSP``:
 ```
 python setup.py <path of Curie_BSP>
 ```
diff --git a/targets/curie_bsp/image/connect.png b/targets/baremetal-sdk/curie-bsp/image/connect.png
similarity index 100%
rename from targets/curie_bsp/image/connect.png
rename to targets/baremetal-sdk/curie-bsp/image/connect.png
diff --git a/targets/curie_bsp/include/inttypes.h b/targets/baremetal-sdk/curie-bsp/include/inttypes.h
similarity index 100%
rename from targets/curie_bsp/include/inttypes.h
rename to targets/baremetal-sdk/curie-bsp/include/inttypes.h
diff --git a/targets/curie_bsp/include/setjmp.h b/targets/baremetal-sdk/curie-bsp/include/setjmp.h
similarity index 100%
rename from targets/curie_bsp/include/setjmp.h
rename to targets/baremetal-sdk/curie-bsp/include/setjmp.h
diff --git a/targets/curie_bsp/jerry_app/arc/defconfig b/targets/baremetal-sdk/curie-bsp/jerry_app/arc/defconfig
similarity index 100%
rename from targets/curie_bsp/jerry_app/arc/defconfig
rename to targets/baremetal-sdk/curie-bsp/jerry_app/arc/defconfig
diff --git a/targets/curie_bsp/jerry_app/arc/main.c b/targets/baremetal-sdk/curie-bsp/jerry_app/arc/main.c
similarity index 100%
rename from targets/curie_bsp/jerry_app/arc/main.c
rename to targets/baremetal-sdk/curie-bsp/jerry_app/arc/main.c
diff --git a/targets/curie_bsp/jerry_app/arc/memory_pool_list.def b/targets/baremetal-sdk/curie-bsp/jerry_app/arc/memory_pool_list.def
similarity index 100%
rename from targets/curie_bsp/jerry_app/arc/memory_pool_list.def
rename to targets/baremetal-sdk/curie-bsp/jerry_app/arc/memory_pool_list.def
diff --git a/targets/curie_bsp/jerry_app/include/project_mapping.h b/targets/baremetal-sdk/curie-bsp/jerry_app/include/project_mapping.h
similarity index 100%
rename from targets/curie_bsp/jerry_app/include/project_mapping.h
rename to targets/baremetal-sdk/curie-bsp/jerry_app/include/project_mapping.h
diff --git a/targets/curie_bsp/jerry_app/quark/defconfig b/targets/baremetal-sdk/curie-bsp/jerry_app/quark/defconfig
similarity index 100%
rename from targets/curie_bsp/jerry_app/quark/defconfig
rename to targets/baremetal-sdk/curie-bsp/jerry_app/quark/defconfig
diff --git a/targets/curie_bsp/jerry_app/quark/main.c b/targets/baremetal-sdk/curie-bsp/jerry_app/quark/main.c
similarity index 100%
rename from targets/curie_bsp/jerry_app/quark/main.c
rename to targets/baremetal-sdk/curie-bsp/jerry_app/quark/main.c
diff --git a/targets/curie_bsp/jerry_app/quark/memory_pool_list.def b/targets/baremetal-sdk/curie-bsp/jerry_app/quark/memory_pool_list.def
similarity index 100%
rename from targets/curie_bsp/jerry_app/quark/memory_pool_list.def
rename to targets/baremetal-sdk/curie-bsp/jerry_app/quark/memory_pool_list.def
diff --git a/targets/curie_bsp/setup.py b/targets/baremetal-sdk/curie-bsp/setup.py
similarity index 94%
rename from targets/curie_bsp/setup.py
rename to targets/baremetal-sdk/curie-bsp/setup.py
index f03497025b..fe6109edbf 100755
--- a/targets/curie_bsp/setup.py
+++ b/targets/baremetal-sdk/curie-bsp/setup.py
@@ -25,15 +25,15 @@ def build_soft_links(project_path, jerry_path):
 
     links = [
         { # arc
-            'src': os.path.join('targets', 'curie_bsp', 'jerry_app', 'arc'),
+            'src': os.path.join('targets', 'baremetal-sdk', 'curie-bsp', 'jerry_app', 'arc'),
             'link_name': 'arc'
         },
         { # include
-            'src': os.path.join('targets', 'curie_bsp', 'jerry_app', 'include'),
+            'src': os.path.join('targets', 'baremetal-sdk', 'curie-bsp', 'jerry_app', 'include'),
             'link_name': 'include'
         },
         { # quark
-            'src': os.path.join('targets', 'curie_bsp', 'jerry_app', 'quark'),
+            'src': os.path.join('targets', 'baremetal-sdk', 'curie-bsp', 'jerry_app', 'quark'),
             'link_name': 'quark'
         },
         { # quark/jerryscript
@@ -76,7 +76,7 @@ def build_jerry_data(jerry_path):
     """
     jerry_sources = []
     jerry_dirs = set()
-    for sub_dir in ['jerry-core', 'jerry-math', os.path.join('targets', 'curie_bsp', 'source')]:
+    for sub_dir in ['jerry-core', 'jerry-math', os.path.join('targets', 'baremetal-sdk', 'curie-bsp', 'source')]:
         for file in find_sources(os.path.normpath(jerry_path), sub_dir):
             path = os.path.join('jerryscript', file)
             jerry_sources.append(path)
@@ -199,7 +199,7 @@ def create_quark_kbuild(project_path, jerry_path):
         'include',
         'jerryscript',
         os.path.join('jerryscript', 'jerry-math', 'include'),
-        os.path.join('jerryscript', 'targets' ,'curie_bsp', 'include')
+        os.path.join('jerryscript', 'targets', 'baremetal-sdk', 'curie-bsp', 'include')
     ] + list(jerry_data['dirs'])
 
     quark_includes = [
@@ -245,7 +245,7 @@ def main(curie_path, project_name, jerry_path):
     project_name = 'curie_bsp_jerry'
 
     file_dir = os.path.dirname(os.path.abspath(__file__))
-    jerry_path = os.path.join(file_dir, "..", "..")
+    jerry_path = os.path.join(file_dir, "..", "..", "..")
     curie_path = os.path.join(os.getcwd(), sys.argv[1])
 
     main(curie_path, project_name, jerry_path)
diff --git a/targets/curie_bsp/source/curie-bsp-port.c b/targets/baremetal-sdk/curie-bsp/source/curie-bsp-port.c
similarity index 100%
rename from targets/curie_bsp/source/curie-bsp-port.c
rename to targets/baremetal-sdk/curie-bsp/source/curie-bsp-port.c
diff --git a/targets/curie_bsp/source/setjmp.S b/targets/baremetal-sdk/curie-bsp/source/setjmp.S
similarity index 100%
rename from targets/curie_bsp/source/setjmp.S
rename to targets/baremetal-sdk/curie-bsp/source/setjmp.S
diff --git a/targets/esp-idf/CMakeLists.txt.example b/targets/baremetal-sdk/esp-idf/CMakeLists.txt.example
similarity index 85%
rename from targets/esp-idf/CMakeLists.txt.example
rename to targets/baremetal-sdk/esp-idf/CMakeLists.txt.example
index 84a5fc4a5b..e7e9d7c0b4 100644
--- a/targets/esp-idf/CMakeLists.txt.example
+++ b/targets/baremetal-sdk/esp-idf/CMakeLists.txt.example
@@ -2,10 +2,10 @@
 # - set the JERRY_DIR wherever the jerryscript source code (the include files) is
 # - a "lib" directory with the 2 libraries below
 
-set(JERRY_DIR ${PROJECT_DIR}/../../jerryscript/)
+set(JERRY_DIR ${PROJECT_DIR}/../../../jerryscript/)
 
 idf_component_register(
-	SRC_DIRS ${JERRY_DIR}/targets/esp-idf
+	SRC_DIRS ${JERRY_DIR}/targets/baremetal-sdk/esp-idf
 	INCLUDE_DIRS ${JERRY_DIR}/jerry-core/include ${JERRY_DIR}/jerry-ext/include
 )
 
diff --git a/targets/esp-idf/README.md b/targets/baremetal-sdk/esp-idf/README.md
similarity index 96%
rename from targets/esp-idf/README.md
rename to targets/baremetal-sdk/esp-idf/README.md
index 2b4d385cf7..ec29ca60e8 100644
--- a/targets/esp-idf/README.md
+++ b/targets/baremetal-sdk/esp-idf/README.md
@@ -16,7 +16,7 @@ Then copy the artifacts 'build/lib/\*.a' in an esp-idf component named 'jerryscr
 set(JERRY_DIR ${PROJECT_DIR}/../../jerryscript/)
 
 idf_component_register(
-	SRC_DIRS ${JERRY_DIR}/targets/esp-idf
+	SRC_DIRS ${JERRY_DIR}/targets/baremetal-sdk/esp-idf
 	INCLUDE_DIRS ${JERRY_DIR}/jerry-core/include ${JERRY_DIR}/jerry-ext/include
 )
 
diff --git a/targets/esp-idf/jerry_module.c b/targets/baremetal-sdk/esp-idf/jerry_module.c
similarity index 100%
rename from targets/esp-idf/jerry_module.c
rename to targets/baremetal-sdk/esp-idf/jerry_module.c
diff --git a/targets/esp-idf/jerry_port.c b/targets/baremetal-sdk/esp-idf/jerry_port.c
similarity index 100%
rename from targets/esp-idf/jerry_port.c
rename to targets/baremetal-sdk/esp-idf/jerry_port.c
diff --git a/targets/esp8266/LICENSE b/targets/baremetal-sdk/esp8266-rtos-sdk/LICENSE
similarity index 100%
rename from targets/esp8266/LICENSE
rename to targets/baremetal-sdk/esp8266-rtos-sdk/LICENSE
diff --git a/targets/esp8266/Makefile b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile
similarity index 99%
rename from targets/esp8266/Makefile
rename to targets/baremetal-sdk/esp8266-rtos-sdk/Makefile
index 5ba77e0e18..fe9ab8cdda 100644
--- a/targets/esp8266/Makefile
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile
@@ -41,7 +41,7 @@ SUBDIRS= user
 endif # } PDIR
 
 # path to the JERRYSCRIPT directory
-JERRYDIR ?= $(CURDIR)/../../..
+JERRYDIR ?= $(CURDIR)/../../../..
 
 LDDIR = $(SDK_PATH)/ld
 
diff --git a/targets/esp8266/Makefile.esp8266 b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266
similarity index 88%
rename from targets/esp8266/Makefile.esp8266
rename to targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266
index 9c131a93ca..f295839947 100644
--- a/targets/esp8266/Makefile.esp8266
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266
@@ -15,7 +15,7 @@
 CURDIR     = `pwd`
 ESP_LIB    = $(SDK_PATH)/lib
 BUILD_DIR  = build/obj-esp8266
-COPYTARGET = targets/esp8266/libs
+COPYTARGET = targets/baremetal-sdk/esp8266-rtos-sdk/libs
 USBDEVICE  ?= /dev/ttyUSB0
 JERRYHEAP  ?= 20
 ESPTOOL    ?= $(ESPTOOL_PATH)/esptool.py
@@ -61,11 +61,11 @@ jerry:
 	cp $(BUILD_DIR)/lib/libjerry-math.a $(COPYTARGET)/
 
 js2c:
-	tools/js2c.py --dest targets/esp8266/include --js-source targets/esp8266/js
+	tools/js2c.py --dest targets/baremetal-sdk/esp8266-rtos-sdk/include --js-source targets/baremetal-sdk/esp8266-rtos-sdk/js
 
 mkbin:
-	make -Ctargets/esp8266 clean
-	make -Ctargets/esp8266 BOOT=new APP=0 SPI_SPEED=40 SPI_MODE=DIO SPI_SIZE_MAP=4
+	make -Ctargets/baremetal-sdk/esp8266-rtos-sdk clean
+	make -Ctargets/baremetal-sdk/esp8266-rtos-sdk BOOT=new APP=0 SPI_SPEED=40 SPI_MODE=DIO SPI_SIZE_MAP=4
 
 check-env:
 ifndef SDK_PATH
diff --git a/targets/esp8266/Makefile.travis b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis
similarity index 93%
rename from targets/esp8266/Makefile.travis
rename to targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis
index 67a75b7774..c2fe5858bb 100644
--- a/targets/esp8266/Makefile.travis
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis
@@ -43,4 +43,4 @@ install: install-apt-get-deps install-noapt
 
 # Build the firmware (ESP8266 with JerryScript).
 script:
-	PATH=$(CURDIR)/../xtensa-lx106-elf/bin:$$PATH $(MAKE) -f ./targets/esp8266/Makefile.esp8266 BIN_PATH=build/obj-esp8266 SDK_PATH=$(CURDIR)/../ESP8266_RTOS_SDK
+	PATH=$(CURDIR)/../xtensa-lx106-elf/bin:$$PATH $(MAKE) -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266 BIN_PATH=build/obj-esp8266 SDK_PATH=$(CURDIR)/../ESP8266_RTOS_SDK
diff --git a/targets/esp8266/docs/ESP-PREREQUISITES.md b/targets/baremetal-sdk/esp8266-rtos-sdk/docs/ESP-PREREQUISITES.md
similarity index 100%
rename from targets/esp8266/docs/ESP-PREREQUISITES.md
rename to targets/baremetal-sdk/esp8266-rtos-sdk/docs/ESP-PREREQUISITES.md
diff --git a/targets/esp8266/include/jerry_extapi.h b/targets/baremetal-sdk/esp8266-rtos-sdk/include/jerry_extapi.h
similarity index 100%
rename from targets/esp8266/include/jerry_extapi.h
rename to targets/baremetal-sdk/esp8266-rtos-sdk/include/jerry_extapi.h
diff --git a/targets/esp8266/include/jerry_run.h b/targets/baremetal-sdk/esp8266-rtos-sdk/include/jerry_run.h
similarity index 100%
rename from targets/esp8266/include/jerry_run.h
rename to targets/baremetal-sdk/esp8266-rtos-sdk/include/jerry_run.h
diff --git a/targets/esp8266/include/user_config.h b/targets/baremetal-sdk/esp8266-rtos-sdk/include/user_config.h
similarity index 100%
rename from targets/esp8266/include/user_config.h
rename to targets/baremetal-sdk/esp8266-rtos-sdk/include/user_config.h
diff --git a/targets/baremetal-sdk/esp8266-rtos-sdk/js/blink.js b/targets/baremetal-sdk/esp8266-rtos-sdk/js/blink.js
new file mode 100644
index 0000000000..d3c6d827b9
--- /dev/null
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/js/blink.js
@@ -0,0 +1,30 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var check = 1;
+
+function blink() {
+  var inp = gpio_get(0);
+  var blk = (check > 8) ? 1 - inp : inp;
+  gpio_set(2, blk);
+  check = check >= 10 ? 1 : check+1;
+}
+
+// GPIO 0 as input
+// GPIO 2 as output
+gpio_dir(0, 0);
+gpio_dir(2, 1);
+
+print("blink js OK");
diff --git a/targets/baremetal-sdk/esp8266-rtos-sdk/js/main.js b/targets/baremetal-sdk/esp8266-rtos-sdk/js/main.js
new file mode 100644
index 0000000000..a25cf06455
--- /dev/null
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/js/main.js
@@ -0,0 +1,20 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+function sysloop(ticknow) {
+  blink();
+};
+print("Random generated number: ", Math.random());
+print("main js OK");
diff --git a/targets/esp8266/ld/eagle.app.v6.ld b/targets/baremetal-sdk/esp8266-rtos-sdk/ld/eagle.app.v6.ld
similarity index 100%
rename from targets/esp8266/ld/eagle.app.v6.ld
rename to targets/baremetal-sdk/esp8266-rtos-sdk/ld/eagle.app.v6.ld
diff --git a/targets/esp8266/readme.md b/targets/baremetal-sdk/esp8266-rtos-sdk/readme.md
similarity index 79%
rename from targets/esp8266/readme.md
rename to targets/baremetal-sdk/esp8266-rtos-sdk/readme.md
index 014971596c..264a0c919d 100644
--- a/targets/esp8266/readme.md
+++ b/targets/baremetal-sdk/esp8266-rtos-sdk/readme.md
@@ -1,6 +1,6 @@
 ### About
 
-Files in this folder (targets/esp8266) are copied from
+Files in this folder (targets/baremetal-sdk/esp8266-rtos-sdk) are copied from
 `examples/project_template` of `esp_iot_rtos_sdk` and modified for JerryScript.
 You can view online from
 [this](https://github.com/espressif/esp_iot_rtos_sdk/tree/master/examples/project_template) page.
@@ -17,7 +17,7 @@ Follow [this](./docs/ESP-PREREQUISITES.md) page to setup build environment
 
 ```
 # assume you are in jerryscript folder
-make -f ./targets/esp8266/Makefile.esp8266
+make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266
 ```
 
 Output files should be placed at $BIN_PATH
@@ -27,13 +27,13 @@ Follow
 [this](http://www.kloppenborg.net/images/blog/esp8266/esp8266-esp12e-specs.pdf) page to get details about this board.
 
 ```
-make -f ./targets/esp8266/Makefile.esp8266 flash
+make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266 flash
 ```
 
 Default USB device is `/dev/ttyUSB0`. If you have different one, give with `USBDEVICE`, like;
 
 ```
-USBDEVICE=/dev/ttyUSB1 make -f ./targets/esp8266/Makefile.esp8266 flash
+USBDEVICE=/dev/ttyUSB1 make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266 flash
 ```
 
 ### 4. Running
@@ -49,12 +49,12 @@ LED should blink on and off every second
 To clean the build result:
 
 ```
-make -f ./targets/esp8266/Makefile.esp8266 clean
+make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266 clean
 ```
 
 To clean the board's flash memory:
 ```
-make -f ./targets/esp8266/Makefile.esp8266 erase_flash
+make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.esp8266 erase_flash
 ```
 
 
diff --git a/targets/esp8266/user/Makefile b/targets/baremetal-sdk/esp8266-rtos-sdk/user/Makefile
similarity index 100%
rename from targets/esp8266/user/Makefile
rename to targets/baremetal-sdk/esp8266-rtos-sdk/user/Makefile
diff --git a/targets/esp8266/user/jerry_extapi.c b/targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_extapi.c
similarity index 100%
rename from targets/esp8266/user/jerry_extapi.c
rename to targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_extapi.c
diff --git a/targets/esp8266/user/jerry_port.c b/targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_port.c
similarity index 100%
rename from targets/esp8266/user/jerry_port.c
rename to targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_port.c
diff --git a/targets/esp8266/user/jerry_run.c b/targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_run.c
similarity index 100%
rename from targets/esp8266/user/jerry_run.c
rename to targets/baremetal-sdk/esp8266-rtos-sdk/user/jerry_run.c
diff --git a/targets/esp8266/user/user_main.c b/targets/baremetal-sdk/esp8266-rtos-sdk/user/user_main.c
similarity index 100%
rename from targets/esp8266/user/user_main.c
rename to targets/baremetal-sdk/esp8266-rtos-sdk/user/user_main.c
diff --git a/targets/particle/Makefile.particle b/targets/baremetal-sdk/particle/Makefile.particle
similarity index 96%
rename from targets/particle/Makefile.particle
rename to targets/baremetal-sdk/particle/Makefile.particle
index 1eb87a31ff..aae1978396 100644
--- a/targets/particle/Makefile.particle
+++ b/targets/baremetal-sdk/particle/Makefile.particle
@@ -29,7 +29,7 @@ PARTICLE_BUILD_CONFIG = \
 	 LIBS=jerry-core \
 	 PLATFORM=photon \
 	 LIB_DIRS=$(BUILD_DIR)/lib \
-	 APPDIR=$(JERRYDIR)/targets/particle/source \
+	 APPDIR=$(JERRYDIR)/targets/baremetal-sdk/particle/source \
 	 TARGET_FILE=jerry_main \
 	 TARGET_DIR=$(BUILD_DIR) \
 	 LDFLAGS=--specs=nano.specs
diff --git a/targets/particle/README.md b/targets/baremetal-sdk/particle/README.md
similarity index 91%
rename from targets/particle/README.md
rename to targets/baremetal-sdk/particle/README.md
index 0e37c4492c..21dc7df0c3 100644
--- a/targets/particle/README.md
+++ b/targets/baremetal-sdk/particle/README.md
@@ -14,7 +14,8 @@ The folder tree related would look like this.
 root
   + jerryscript
   |  + targets
-  |      + particle
+  |      + os
+  |        + particle
   + particle
   |  + firmware
 ```
@@ -53,7 +54,7 @@ make PLATFORM=photon clean all program-dfu
 ```
 # assume you are in root folder
 cd jerryscript
-make -f ./targets/particle/Makefile.particle
+make -f ./targets/baremetal-sdk/particle/Makefile.particle
 ```
 
 This will create a binary file in the `/build/particle/` folder:
@@ -70,7 +71,7 @@ Make sure you put your Photon in DFU mode.
 Alternatively, you can make your life a bit easier by using the make command to invoke dfu-util:
 
 ```
-make -f targets/particle/Makefile.particle flash
+make -f targets/baremetal-sdk/particle/Makefile.particle flash
 ```
 
 You can also use this dfu-util command directly to upload your BIN file to the Photon’s application memory:
@@ -83,7 +84,7 @@ dfu-util -d 2b04:d006 -a 0 -i 0 -s 0x80A0000:leave -D build/particle/jerry_main.
 
 To clean the build result:
 ```
-make -f targets/particle/Makefile.particle clean
+make -f targets/baremetal-sdk/particle/Makefile.particle clean
 ```
 
 ### Running the example
diff --git a/targets/particle/source/main.cpp b/targets/baremetal-sdk/particle/source/main.cpp
similarity index 100%
rename from targets/particle/source/main.cpp
rename to targets/baremetal-sdk/particle/source/main.cpp
diff --git a/targets/esp8266/js/blink.js b/targets/esp8266/js/blink.js
deleted file mode 100644
index b71a626ce6..0000000000
--- a/targets/esp8266/js/blink.js
+++ /dev/null
@@ -1,15 +0,0 @@
-var check = 1;
-
-function blink() {
-  var inp = gpio_get(0);
-  var blk = (check > 8) ? 1 - inp : inp;
-  gpio_set(2, blk);
-  check = check >= 10 ? 1 : check+1;
-}
-
-// GPIO 0 as input
-// GPIO 2 as output
-gpio_dir(0, 0);
-gpio_dir(2, 1);
-
-print("blink js OK");
diff --git a/targets/esp8266/js/main.js b/targets/esp8266/js/main.js
deleted file mode 100644
index d5189a7065..0000000000
--- a/targets/esp8266/js/main.js
+++ /dev/null
@@ -1,5 +0,0 @@
-function sysloop(ticknow) {
-  blink();
-};
-print("Random generated number: ", Math.random());
-print("main js OK");
diff --git a/targets/mbedos5/.gitignore b/targets/os/mbedos5/.gitignore
similarity index 100%
rename from targets/mbedos5/.gitignore
rename to targets/os/mbedos5/.gitignore
diff --git a/targets/mbedos5/Makefile b/targets/os/mbedos5/Makefile
similarity index 85%
rename from targets/mbedos5/Makefile
rename to targets/os/mbedos5/Makefile
index 825d44f413..8b57670149 100644
--- a/targets/mbedos5/Makefile
+++ b/targets/os/mbedos5/Makefile
@@ -23,7 +23,7 @@ DEBUG?=0
 NO_JS?=0
 MBED_VERBOSE?=0
 
-MBED_CLI_FLAGS=-j0 --source . --source ../../
+MBED_CLI_FLAGS=-j0 --source . --source ../../../
 
 EXTRA_SRC=
 
@@ -52,11 +52,11 @@ MBED_CLI_FLAGS += -D "JERRY_GLOBAL_HEAP_SIZE=$(HEAPSIZE)"
 MBED_CLI_FLAGS += -t GCC_ARM
 
 .PHONY: all js2c getlibs rebuild library
-all: source/jerry-targetjs.h source/pins.cpp .mbed ../../.mbedignore
+all: source/jerry-targetjs.h source/pins.cpp .mbed ../../../.mbedignore
 	mbed target $(BOARD)
 	mbed compile $(MBED_CLI_FLAGS)
 
-library: .mbed ../../.mbedignore
+library: .mbed ../../../.mbedignore
 	# delete encoded js code if it exists
 	rm -f source/jerry-targetjs.h
 	mbed target $(BOARD)
@@ -66,7 +66,7 @@ clean:
 	rm -rf ./BUILD/$(BOARD)
 
 js2c: js/main.js js/flash_leds.js
-	python ../../tools/js2c.py --ignore pins.js
+	python ../../../tools/js2c.py --ignore pins.js
 
 source/pins.cpp:
 	python tools/generate_pins.py ${BOARD}
@@ -86,9 +86,9 @@ getlibs: .mbed
 	mbed target $(BOARD)
 	mbed deploy
 
-../../.mbedignore:
+../../../.mbedignore:
 ifeq ($(OS),Windows_NT)
-	copy template-mbedignore.txt ..\..\.mbedignore
+	copy template-mbedignore.txt ..\..\..\.mbedignore
 else
-	cp ./template-mbedignore.txt ../../.mbedignore
+	cp ./template-mbedignore.txt ../../../.mbedignore
 endif
diff --git a/targets/mbedos5/Makefile.travis b/targets/os/mbedos5/Makefile.travis
similarity index 86%
rename from targets/mbedos5/Makefile.travis
rename to targets/os/mbedos5/Makefile.travis
index a94e59b688..94b64f5554 100644
--- a/targets/mbedos5/Makefile.travis
+++ b/targets/os/mbedos5/Makefile.travis
@@ -24,10 +24,10 @@ all:
 # Deploy Mbed and install Mbed Python dependencies.
 install:
 	pip install mbed-cli
-	cd targets/mbedos5 && mbed deploy
+	cd targets/os/mbedos5 && mbed deploy
 	pip install idna==2.5 # FIXME: workaround
-	pip install -r targets/mbedos5/mbed-os/requirements.txt
-	pip install -r targets/mbedos5/tools/requirements.txt
+	pip install -r targets/os/mbedos5/mbed-os/requirements.txt
+	pip install -r targets/os/mbedos5/tools/requirements.txt
 
 
 ## Targets for building Mbed OS 5 with JerryScript.
@@ -37,4 +37,4 @@ script:
 	# HACK: `EXTRA_SRC[_MOD]` are abused to pass `--library` to `mbed compile` in the `all` make target that builds an app
 	# HACK: this is needed because the Mbed OS 5 target code does not contain any `main` function, so the `all` make target does not link
 	# HACK: but the `library` make target does not build either because the launcher sources require `jerry-targetjs.h` that are explicitly not generated for libraries
-	$(MAKE) -C targets/mbedos5 BOARD=K64F EXTRA_SRC=dummy EXTRA_SRC_MOD=--library
+	$(MAKE) -C targets/os/mbedos5 BOARD=K64F EXTRA_SRC=dummy EXTRA_SRC_MOD=--library
diff --git a/targets/mbedos5/README.md b/targets/os/mbedos5/README.md
similarity index 100%
rename from targets/mbedos5/README.md
rename to targets/os/mbedos5/README.md
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/AnalogIn-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/AnalogIn-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/AnalogIn-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/AnalogIn-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/DigitalOut-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/DigitalOut-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/DigitalOut-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/DigitalOut-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/I2C-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/I2C-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/I2C-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/I2C-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/InterruptIn-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/InterruptIn-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/InterruptIn-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/InterruptIn-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/PwmOut-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/PwmOut-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/PwmOut-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/PwmOut-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/lib_drivers.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/lib_drivers.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/lib_drivers.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/lib_drivers.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setInterval-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setInterval-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setInterval-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setInterval-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setTimeout-js.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setTimeout-js.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setTimeout-js.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/setTimeout-js.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/AnalogIn-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/AnalogIn-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/AnalogIn-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/AnalogIn-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/DigitalOut-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/DigitalOut-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/DigitalOut-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/DigitalOut-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/I2C-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/I2C-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/I2C-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/I2C-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/InterruptIn-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/InterruptIn-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/InterruptIn-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/InterruptIn-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/PwmOut-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/PwmOut-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/PwmOut-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/PwmOut-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setInterval-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setInterval-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setInterval-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setInterval-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setTimeout-js.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setTimeout-js.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setTimeout-js.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-drivers/source/setTimeout-js.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/BoundCallback.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/BoundCallback.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/BoundCallback.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/BoundCallback.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/EventLoop.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/EventLoop.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/EventLoop.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/EventLoop.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/source/EventLoop.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/source/EventLoop.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/source/EventLoop.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-event-loop/source/EventLoop.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/launcher.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/launcher.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/launcher.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/launcher.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/setup.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/setup.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/setup.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/setup.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/launcher.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/launcher.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/launcher.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/launcher.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/setup.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/setup.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/setup.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-launcher/source/setup.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/registry.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/registry.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/registry.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/registry.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/registry.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/registry.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/registry.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/registry.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/wrap_tools.cpp b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/wrap_tools.cpp
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/wrap_tools.cpp
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/source/wrap_tools.cpp
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/wrap_tools.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/wrap_tools.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/wrap_tools.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-library-registry/wrap_tools.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/js_source.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/js_source.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/js_source.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/js_source.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/logging.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/logging.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/logging.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/logging.h
diff --git a/targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/wrappers.h b/targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/wrappers.h
similarity index 100%
rename from targets/mbedos5/jerryscript-mbed/jerryscript-mbed-util/wrappers.h
rename to targets/os/mbedos5/jerryscript-mbed/jerryscript-mbed-util/wrappers.h
diff --git a/targets/mbedos5/js/flash_leds.js b/targets/os/mbedos5/js/flash_leds.js
similarity index 100%
rename from targets/mbedos5/js/flash_leds.js
rename to targets/os/mbedos5/js/flash_leds.js
diff --git a/targets/mbedos5/js/main.js b/targets/os/mbedos5/js/main.js
similarity index 100%
rename from targets/mbedos5/js/main.js
rename to targets/os/mbedos5/js/main.js
diff --git a/targets/mbedos5/mbed-os.lib b/targets/os/mbedos5/mbed-os.lib
similarity index 100%
rename from targets/mbedos5/mbed-os.lib
rename to targets/os/mbedos5/mbed-os.lib
diff --git a/targets/mbedos5/mbed_app.json b/targets/os/mbedos5/mbed_app.json
similarity index 100%
rename from targets/mbedos5/mbed_app.json
rename to targets/os/mbedos5/mbed_app.json
diff --git a/targets/mbedos5/source/jerry_port_mbed.c b/targets/os/mbedos5/source/jerry_port_mbed.c
similarity index 100%
rename from targets/mbedos5/source/jerry_port_mbed.c
rename to targets/os/mbedos5/source/jerry_port_mbed.c
diff --git a/targets/mbedos5/template-mbedignore.txt b/targets/os/mbedos5/template-mbedignore.txt
similarity index 100%
rename from targets/mbedos5/template-mbedignore.txt
rename to targets/os/mbedos5/template-mbedignore.txt
diff --git a/targets/mbedos5/tools/check_pins.sh b/targets/os/mbedos5/tools/check_pins.sh
similarity index 100%
rename from targets/mbedos5/tools/check_pins.sh
rename to targets/os/mbedos5/tools/check_pins.sh
diff --git a/targets/mbedos5/tools/cmsis.h b/targets/os/mbedos5/tools/cmsis.h
similarity index 100%
rename from targets/mbedos5/tools/cmsis.h
rename to targets/os/mbedos5/tools/cmsis.h
diff --git a/targets/mbedos5/tools/generate_pins.py b/targets/os/mbedos5/tools/generate_pins.py
similarity index 99%
rename from targets/mbedos5/tools/generate_pins.py
rename to targets/os/mbedos5/tools/generate_pins.py
index a35bca4a5e..e5210d01ae 100644
--- a/targets/mbedos5/tools/generate_pins.py
+++ b/targets/os/mbedos5/tools/generate_pins.py
@@ -17,7 +17,7 @@
 Generate pins.cpp for a specified target, using target definitions from the
 mbed OS source tree.
 
-It's expecting to be run from the targets/mbedos5 directory.
+It's expecting to be run from the targets/os/mbedos5 directory.
 """
 
 from __future__ import print_function
diff --git a/targets/mbedos5/tools/jshint.conf b/targets/os/mbedos5/tools/jshint.conf
similarity index 100%
rename from targets/mbedos5/tools/jshint.conf
rename to targets/os/mbedos5/tools/jshint.conf
diff --git a/targets/mbedos5/tools/requirements.txt b/targets/os/mbedos5/tools/requirements.txt
similarity index 100%
rename from targets/mbedos5/tools/requirements.txt
rename to targets/os/mbedos5/tools/requirements.txt
diff --git a/targets/nuttx-stm32f4/.gitignore b/targets/os/nuttx/.gitignore
similarity index 100%
rename from targets/nuttx-stm32f4/.gitignore
rename to targets/os/nuttx/.gitignore
diff --git a/targets/nuttx-stm32f4/Kconfig b/targets/os/nuttx/Kconfig
similarity index 100%
rename from targets/nuttx-stm32f4/Kconfig
rename to targets/os/nuttx/Kconfig
diff --git a/targets/nuttx-stm32f4/Make.defs b/targets/os/nuttx/Make.defs
similarity index 100%
rename from targets/nuttx-stm32f4/Make.defs
rename to targets/os/nuttx/Make.defs
diff --git a/targets/nuttx-stm32f4/Makefile b/targets/os/nuttx/Makefile
similarity index 97%
rename from targets/nuttx-stm32f4/Makefile
rename to targets/os/nuttx/Makefile
index 48193066e3..f0d46272be 100644
--- a/targets/nuttx-stm32f4/Makefile
+++ b/targets/os/nuttx/Makefile
@@ -21,7 +21,7 @@ STACKSIZE = $(CONFIG_INTERPRETERS_JERRYSCRIPT_STACKSIZE)
 
 # Path to the JerryScript and NuttX projects. If not specified, it is
 # supposed that JerryScript is located next to the nuttx folder.
-JERRYSCRIPT_ROOT_DIR ?= ../../../jerryscript
+JERRYSCRIPT_ROOT_DIR ?= ../../../../jerryscript
 NUTTX_ROOT_DIR ?= $(JERRYSCRIPT_ROOT_DIR)/../nuttx
 
 CFLAGS += -std=c99
diff --git a/targets/nuttx-stm32f4/Makefile.travis b/targets/os/nuttx/Makefile.travis
similarity index 97%
rename from targets/nuttx-stm32f4/Makefile.travis
rename to targets/os/nuttx/Makefile.travis
index fe33b295af..aaa9e61e8d 100644
--- a/targets/nuttx-stm32f4/Makefile.travis
+++ b/targets/os/nuttx/Makefile.travis
@@ -51,7 +51,7 @@ install: install-apt-get-deps install-noapt
 
 # Link in the NuttX JerryScript target directory under the NuttX apps tree.
 script-add-jerryscript-app:
-	ln -s ../../jerryscript/targets/nuttx-stm32f4 ../apps/interpreters/jerryscript
+	ln -s ../../jerryscript/targets/os/nuttx ../apps/interpreters/jerryscript
 
 # Configure USB shell.
 script-configure-usbnsh:
diff --git a/targets/nuttx-stm32f4/README.md b/targets/os/nuttx/README.md
similarity index 98%
rename from targets/nuttx-stm32f4/README.md
rename to targets/os/nuttx/README.md
index a323390348..a33be14a9b 100644
--- a/targets/nuttx-stm32f4/README.md
+++ b/targets/os/nuttx/README.md
@@ -29,7 +29,8 @@ The following directory structure is created after these commands:
 jerry-nuttx
   + jerryscript
   |  + targets
-  |     + nuttx-stm32f4
+  |      + os
+  |        + nuttx
   + nuttx
   + apps
   + tools
@@ -63,10 +64,10 @@ Move JerryScript application files to `apps/interpreters/jerryscript` folder.
 ```sh
 # Assuming you are in jerry-nuttx folder.
 mkdir -p apps/interpreters/jerryscript
-cp jerryscript/targets/nuttx-stm32f4/* apps/interpreters/jerryscript/
+cp jerryscript/targets/os/nuttx/* apps/interpreters/jerryscript/
 
 # Or more simply:
-# ln -s jerryscript/targets/nuttx-stm32f4 apps/interpreters/jerryscript
+# ln -s jerryscript/targets/os/nuttx apps/interpreters/jerryscript
 ```
 
 #### 4. Build kconfig-frontend to configure NuttX
diff --git a/targets/nuttx-stm32f4/jerry_main.c b/targets/os/nuttx/jerry_main.c
similarity index 100%
rename from targets/nuttx-stm32f4/jerry_main.c
rename to targets/os/nuttx/jerry_main.c
diff --git a/targets/nuttx-stm32f4/jerry_module.c b/targets/os/nuttx/jerry_module.c
similarity index 100%
rename from targets/nuttx-stm32f4/jerry_module.c
rename to targets/os/nuttx/jerry_module.c
diff --git a/targets/nuttx-stm32f4/jerry_port.c b/targets/os/nuttx/jerry_port.c
similarity index 100%
rename from targets/nuttx-stm32f4/jerry_port.c
rename to targets/os/nuttx/jerry_port.c
diff --git a/targets/nuttx-stm32f4/setjmp.S b/targets/os/nuttx/setjmp.S
similarity index 100%
rename from targets/nuttx-stm32f4/setjmp.S
rename to targets/os/nuttx/setjmp.S
diff --git a/targets/nuttx-stm32f4/setjmp.h b/targets/os/nuttx/setjmp.h
similarity index 100%
rename from targets/nuttx-stm32f4/setjmp.h
rename to targets/os/nuttx/setjmp.h
diff --git a/targets/openwrt/readme.md b/targets/os/openwrt/readme.md
similarity index 100%
rename from targets/openwrt/readme.md
rename to targets/os/openwrt/readme.md
diff --git a/targets/riot-stm32f4/Makefile b/targets/os/riot/Makefile
similarity index 94%
rename from targets/riot-stm32f4/Makefile
rename to targets/os/riot/Makefile
index e8030cab08..811041268e 100644
--- a/targets/riot-stm32f4/Makefile
+++ b/targets/os/riot/Makefile
@@ -18,17 +18,17 @@ APPLICATION = riot_jerryscript
 # default BOARD enviroment
 BOARD ?= stm32f4discovery
 
-# path to jerryscript/targets/riot-stm32f4
+# path to jerryscript/targets/os/riot
 TARGET_DIR = $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 
 # path to the JERRYSCRIPT directory
-JERRYDIR ?= $(TARGET_DIR)/../..
+JERRYDIR ?= $(TARGET_DIR)/../../..
 
 # path to the RIOT base directory
 RIOTBASE ?= $(JERRYDIR)/../RIOT
 
 # path to the application directory
-APPDIR ?= $(JERRYDIR)/targets/riot-stm32f4/source
+APPDIR ?= $(JERRYDIR)/targets/os/riot/source
 
 # path to the binary directory
 BUILDDIR ?= $(JERRYDIR)/build/riot-stm32f4
diff --git a/targets/riot-stm32f4/Makefile.travis b/targets/os/riot/Makefile.travis
similarity index 96%
rename from targets/riot-stm32f4/Makefile.travis
rename to targets/os/riot/Makefile.travis
index a4bf710174..6b20605921 100644
--- a/targets/riot-stm32f4/Makefile.travis
+++ b/targets/os/riot/Makefile.travis
@@ -37,4 +37,4 @@ install: install-apt-get-deps install-noapt
 
 # Build the firmware (RIOT with JerryScript).
 script:
-	$(MAKE) -f ./targets/riot-stm32f4/Makefile
+	$(MAKE) -f ./targets/os/riot/Makefile
diff --git a/targets/riot-stm32f4/README.md b/targets/os/riot/README.md
similarity index 94%
rename from targets/riot-stm32f4/README.md
rename to targets/os/riot/README.md
index 9810293e0f..3b59b5cb1c 100644
--- a/targets/riot-stm32f4/README.md
+++ b/targets/os/riot/README.md
@@ -35,7 +35,8 @@ The following directory structure has been created:
 jerry-riot
   + jerryscript
   |  + targets
-  |     + riot-stm32f4
+  |      + os
+  |        + riot
   + RIOT
 ```
 
@@ -43,7 +44,7 @@ jerry-riot
 
 ```
 # Assuming you are in jerry-riot folder.
-make BOARD=stm32f4discovery -f jerryscript/targets/riot-stm32f4/Makefile
+make BOARD=stm32f4discovery -f jerryscript/targets/os/riot/Makefile
 ```
 
 The created binary is a `riot_jerryscript.elf` named file located in `jerryscript/build/riot-stm32f4/bin/` folder.
@@ -54,7 +55,7 @@ Connect Mini-USB for charging and flashing the device.
 
 ```
 # Assuming you are in jerry-riot folder.
-make BOARD=stm32f4discovery -f jerryscript/targets/riot-stm32f4/Makefile flash
+make BOARD=stm32f4discovery -f jerryscript/targets/os/riot/Makefile flash
 ```
 
 Note: `ST-LINK` also can be used that is described at [this page](https://github.com/RIOT-OS/RIOT/wiki/ST-LINK-tool).
diff --git a/targets/riot-stm32f4/source/main-riotos.c b/targets/os/riot/source/main-riotos.c
similarity index 100%
rename from targets/riot-stm32f4/source/main-riotos.c
rename to targets/os/riot/source/main-riotos.c
diff --git a/targets/zephyr/CMakeLists.txt b/targets/os/zephyr/CMakeLists.txt
similarity index 97%
rename from targets/zephyr/CMakeLists.txt
rename to targets/os/zephyr/CMakeLists.txt
index ce6be95efb..de3da6b4e7 100644
--- a/targets/zephyr/CMakeLists.txt
+++ b/targets/os/zephyr/CMakeLists.txt
@@ -17,7 +17,7 @@ cmake_minimum_required(VERSION 3.20.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(NONE)
 
-set(JERRY_BASE ${CMAKE_SOURCE_DIR}/../..)
+set(JERRY_BASE ${CMAKE_SOURCE_DIR}/../../..)
 
 # Build JerryScript
 execute_process(COMMAND ${JERRY_BASE}/tools/build.py
diff --git a/targets/zephyr/Makefile.travis b/targets/os/zephyr/Makefile.travis
similarity index 98%
rename from targets/zephyr/Makefile.travis
rename to targets/os/zephyr/Makefile.travis
index 93f0996693..be05b271c3 100644
--- a/targets/zephyr/Makefile.travis
+++ b/targets/os/zephyr/Makefile.travis
@@ -60,4 +60,4 @@ SHELL=bash
 script: init-west
 	export ZEPHYR_TOOLCHAIN_VARIANT=zephyr && \
 	export ZEPHYR_SDK_INSTALL_DIR=$(CURDIR)/../zephyr-toolchain-0.13.2 && \
-	west build -d $(CURDIR)/../build -p auto -b stm32f4_disco targets/zephyr/ -- -G'Unix Makefiles'
+	west build -d $(CURDIR)/../build -p auto -b stm32f4_disco targets/os/zephyr/ -- -G'Unix Makefiles'
diff --git a/targets/zephyr/README.md b/targets/os/zephyr/README.md
similarity index 97%
rename from targets/zephyr/README.md
rename to targets/os/zephyr/README.md
index 2cdd4f1793..0b9056cf06 100644
--- a/targets/zephyr/README.md
+++ b/targets/os/zephyr/README.md
@@ -26,7 +26,8 @@ The following directory structure has been created:
 jerry-zephyr
   + jerryscript
   |  + targets
-  |     + zephyr
+  |      + os
+  |        + zephyr
   + zephyr
   + zephyr-toolchain-arm-0.13.2-linux-x86_64-setup.run
 ```
@@ -66,7 +67,7 @@ west zephyr-export
 
 ```
 # Assuming you are in jerry-zephyr folder.
-west build -p auto -b stm32f4_disco jerryscript/targets/zephyr/
+west build -p auto -b stm32f4_disco jerryscript/targets/os/zephyr/
 ```
 
 The created binary is a `zephyr.elf` named file located in `jerry-zephyr/build/zephyr/bin/` folder.
diff --git a/targets/zephyr/prj.conf b/targets/os/zephyr/prj.conf
similarity index 100%
rename from targets/zephyr/prj.conf
rename to targets/os/zephyr/prj.conf
diff --git a/targets/zephyr/src/getline-zephyr.c b/targets/os/zephyr/src/getline-zephyr.c
similarity index 100%
rename from targets/zephyr/src/getline-zephyr.c
rename to targets/os/zephyr/src/getline-zephyr.c
diff --git a/targets/zephyr/src/getline-zephyr.h b/targets/os/zephyr/src/getline-zephyr.h
similarity index 100%
rename from targets/zephyr/src/getline-zephyr.h
rename to targets/os/zephyr/src/getline-zephyr.h
diff --git a/targets/zephyr/src/jerry-module.c b/targets/os/zephyr/src/jerry-module.c
similarity index 100%
rename from targets/zephyr/src/jerry-module.c
rename to targets/os/zephyr/src/jerry-module.c
diff --git a/targets/zephyr/src/jerry-port.c b/targets/os/zephyr/src/jerry-port.c
similarity index 100%
rename from targets/zephyr/src/jerry-port.c
rename to targets/os/zephyr/src/jerry-port.c
diff --git a/targets/zephyr/src/main-zephyr.c b/targets/os/zephyr/src/main-zephyr.c
similarity index 100%
rename from targets/zephyr/src/main-zephyr.c
rename to targets/os/zephyr/src/main-zephyr.c