diff --git a/src/generator/default/transformer.php b/src/generator/default/transformer.php
index 00462b21..6847e514 100644
--- a/src/generator/default/transformer.php
+++ b/src/generator/default/transformer.php
@@ -43,6 +43,15 @@ public function include<?=$relation->getCamelName()?>(<?=$transformer->dbModel->
         return $this->collection($relation, $transformer, '<?=$transformer->makeResourceKey($relation->getClassKey())?>');
 <?php endif;?>
     }
-<?php endforeach;
-endif;?>
+<?php endforeach;?>
+<?php foreach ($transformer->many2Many as $relation):?>
+
+    public function include<?=$relation->getCamelName()?>(<?=$transformer->dbModel->getClassName()?> $model)
+    {
+        $relation = $model-><?=Inflector::variablize($relation->name)?>;
+        $transformer = new <?=Inflector::singularize($relation->getRelatedClassName())?>Transformer();
+        return $this->collection($relation, $transformer, '<?=$transformer->makeResourceKey($relation->relatedSchemaName)?>');
+    }
+<?php endforeach;?>
+<?php endif;?>
 }
diff --git a/src/lib/items/Transformer.php b/src/lib/items/Transformer.php
index ab8b5d6b..9d2b0a3d 100644
--- a/src/lib/items/Transformer.php
+++ b/src/lib/items/Transformer.php
@@ -11,12 +11,13 @@
 use yii\helpers\Inflector;
 
 /**
- * @property-read string                                                $name
- * @property-read array                                                 $defaultRelations
- * @property-read string                                                $modelFQN
- * @property-read string                                                $fQN
- * @property-read array|\cebe\yii2openapi\lib\items\AttributeRelation[] $relations
- * @property-read array                                                 $availableRelations
+ * @property-read string                                                 $name
+ * @property-read array                                                  $defaultRelations
+ * @property-read string                                                 $modelFQN
+ * @property-read string                                                 $fQN
+ * @property-read array|\cebe\yii2openapi\lib\items\AttributeRelation[]  $relations
+ * @property-read \cebe\yii2openapi\lib\items\ManyToManyRelation[]|array $many2Many
+ * @property-read array                                                  $availableRelations
  */
 class Transformer extends BaseObject
 {
@@ -77,6 +78,14 @@ public function getRelations(): array
         return $this->dbModel->relations;
     }
 
+    /**
+     * @return array|\cebe\yii2openapi\lib\items\ManyToManyRelation[]
+     */
+    public function getMany2Many(): array
+    {
+        return $this->dbModel->many2many;
+    }
+
     public function getDefaultRelations(): array
     {
         return [];
@@ -84,11 +93,12 @@ public function getDefaultRelations(): array
 
     public function getAvailableRelations(): array
     {
-        return \array_keys($this->dbModel->relations);
+        return array_merge(array_keys($this->dbModel->relations), array_keys($this->dbModel->many2many));
     }
 
     public function makeResourceKey(string $value): string
     {
-        return $this->singularResourceKey ? Inflector::singularize($value): Inflector::pluralize($value);
+        $value = $this->singularResourceKey ? Inflector::singularize($value): Inflector::pluralize($value);
+        return strtolower(Inflector::camel2id($value, '_'));
     }
 }
diff --git a/tests/specs/many2many.yaml b/tests/specs/many2many.yaml
index d48be3f1..1cf439d8 100644
--- a/tests/specs/many2many.yaml
+++ b/tests/specs/many2many.yaml
@@ -7,13 +7,13 @@ info:
 servers:
   - url: http://blog.dummy.io/v2
 paths:
-  /some:
+  /posts:
     get:
       summary: dummy path
       operationId: showDummy
       responses:
         '200':
-          description: Some response
+          $ref: '#/components/responses/PostListResponse'
 components:
   schemas:
     Post:
@@ -86,3 +86,38 @@ components:
           $ref: '#/components/schemas/Photo'
         post:
           $ref: '#/components/schemas/Post'
+    _PostResource:
+      type: object
+      properties:
+        id:
+          type: integer
+          example: 1
+        type:
+          type: string
+        attributes:
+          $ref: '#/components/schemas/Post'
+        links:
+          type: object
+        relationships:
+          type: object
+  responses:
+    PostResponse:
+      description: Single post info
+      content:
+        application/vnd.api+json:
+          schema:
+            type: object
+            properties:
+              data:
+                $ref: '#/components/schemas/_PostResource'
+    PostListResponse:
+      description: Posts List
+      content:
+        application/vnd.api+json:
+          schema:
+            type: object
+            properties:
+              data:
+                type: array
+                items:
+                  $ref: '#/components/schemas/_PostResource'