diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 107764ba4d539e..39930b5aa1d1f4 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -1196,6 +1196,7 @@ or `the MSDN <https://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx>`_ on Windo
 
    - :data:`RWF_DSYNC`
    - :data:`RWF_SYNC`
+   - :data:`RWF_APPEND`
 
    Return the total number of bytes actually written.
 
@@ -1230,6 +1231,16 @@ or `the MSDN <https://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx>`_ on Windo
    .. versionadded:: 3.7
 
 
+.. data:: RWF_APPEND
+
+   Append data to the end of the file. See the description of the flag 'O_APPEND' in ''os.open()''.
+   The *offset* field is ignored. The file *offset* is not changed.
+
+   .. availability:: Linux 4.16 and newer.
+
+   .. versionadded:: 3.8
+
+
 .. function:: read(fd, n)
 
    Read at most *n* bytes from file descriptor *fd*.
diff --git a/Misc/NEWS.d/next/Library/2019-06-01-21-58-50.bpo-37129.Uzw_V-.rst b/Misc/NEWS.d/next/Library/2019-06-01-21-58-50.bpo-37129.Uzw_V-.rst
new file mode 100644
index 00000000000000..3bbc2e04e11032
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-06-01-21-58-50.bpo-37129.Uzw_V-.rst
@@ -0,0 +1 @@
+add RWF_APPEND flag
\ No newline at end of file
diff --git a/Modules/clinic/posixmodule.c.h b/Modules/clinic/posixmodule.c.h
index 22cb94761de5c7..97aa10c74e72cc 100644
--- a/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@ -5334,6 +5334,7 @@ PyDoc_STRVAR(os_pwritev__doc__,
 "\n"
 "- RWF_DSYNC\n"
 "- RWF_SYNC\n"
+"- RWF_APPEND\n"
 "\n"
 "Using non-zero flags requires Linux 4.7 or newer.");
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 8f6cffffcdfbe8..a9c82008ff0198 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -14023,6 +14023,9 @@ all_ins(PyObject *m)
 #ifdef RWF_NOWAIT
     if (PyModule_AddIntConstant(m, "RWF_NOWAIT", RWF_NOWAIT)) return -1;
 #endif
+#ifdef RWF_APPEND
+    if (PyModule_AddIntConstant(m, "RWF_APPEND", RWF_APPEND)) return -1;
+#endif
 
 /* constants for posix_spawn */
 #ifdef HAVE_POSIX_SPAWN