diff --git a/modules/openapi-generator/src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing.yaml
index 6e228f38056..4a759f4e5c9 100644
--- a/modules/openapi-generator/src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -1985,6 +1985,19 @@ components:
       enum:
         - admin
         - user
+    AllOfWithNestedOneOf:
+      type: object
+      title: allOf with nested oneOf model (inline)
+      allOf:
+        - $ref: '#/components/schemas/Tag'
+        - type: object
+          properties: 
+            inner_name:
+              type: string
+            nested_oneof:
+              oneOf:
+                - $ref: '#/components/schemas/BasquePig'
+                - $ref: '#/components/schemas/DanishPig'
     Pig:
       oneOf:
         - $ref: '#/components/schemas/BasquePig'
diff --git a/samples/openapi3/client/petstore/python-nextgen/.openapi-generator/FILES b/samples/openapi3/client/petstore/python-nextgen/.openapi-generator/FILES
index b8e0a20aec6..3eaad3ada2a 100755
--- a/samples/openapi3/client/petstore/python-nextgen/.openapi-generator/FILES
+++ b/samples/openapi3/client/petstore/python-nextgen/.openapi-generator/FILES
@@ -4,6 +4,8 @@
 .travis.yml
 README.md
 docs/AdditionalPropertiesClass.md
+docs/AllOfWithNestedOneOf.md
+docs/AllOfWithNestedOneOfAllOf.md
 docs/AllOfWithSingleRef.md
 docs/Animal.md
 docs/AnotherFakeApi.md
@@ -83,6 +85,8 @@ petstore_api/configuration.py
 petstore_api/exceptions.py
 petstore_api/models/__init__.py
 petstore_api/models/additional_properties_class.py
+petstore_api/models/all_of_with_nested_one_of.py
+petstore_api/models/all_of_with_nested_one_of_all_of.py
 petstore_api/models/all_of_with_single_ref.py
 petstore_api/models/animal.py
 petstore_api/models/any_of_color.py
diff --git a/samples/openapi3/client/petstore/python-nextgen/README.md b/samples/openapi3/client/petstore/python-nextgen/README.md
index 595e187329e..7f25bbea48e 100755
--- a/samples/openapi3/client/petstore/python-nextgen/README.md
+++ b/samples/openapi3/client/petstore/python-nextgen/README.md
@@ -128,6 +128,8 @@ Class | Method | HTTP request | Description
 ## Documentation For Models
 
  - [AdditionalPropertiesClass](docs/AdditionalPropertiesClass.md)
+ - [AllOfWithNestedOneOf](docs/AllOfWithNestedOneOf.md)
+ - [AllOfWithNestedOneOfAllOf](docs/AllOfWithNestedOneOfAllOf.md)
  - [AllOfWithSingleRef](docs/AllOfWithSingleRef.md)
  - [Animal](docs/Animal.md)
  - [AnyOfColor](docs/AnyOfColor.md)
diff --git a/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOf.md b/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOf.md
new file mode 100644
index 00000000000..182feeff2c4
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOf.md
@@ -0,0 +1,31 @@
+# AllOfWithNestedOneOf
+
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**id** | **int** |  | [optional] 
+**name** | **str** |  | [optional] 
+**inner_name** | **str** |  | [optional] 
+**nested_oneof** | [**OneOfBasquePigDanishPig**](OneOfBasquePigDanishPig.md) |  | [optional] 
+
+## Example
+
+```python
+from petstore_api.models.all_of_with_nested_one_of import AllOfWithNestedOneOf
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of AllOfWithNestedOneOf from a JSON string
+all_of_with_nested_one_of_instance = AllOfWithNestedOneOf.from_json(json)
+# print the JSON string representation of the object
+print AllOfWithNestedOneOf.to_json()
+
+# convert the object into a dict
+all_of_with_nested_one_of_dict = all_of_with_nested_one_of_instance.to_dict()
+# create an instance of AllOfWithNestedOneOf from a dict
+all_of_with_nested_one_of_form_dict = all_of_with_nested_one_of.from_dict(all_of_with_nested_one_of_dict)
+```
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOfAllOf.md b/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOfAllOf.md
new file mode 100644
index 00000000000..02e5960d2c2
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/docs/AllOfWithNestedOneOfAllOf.md
@@ -0,0 +1,29 @@
+# AllOfWithNestedOneOfAllOf
+
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**inner_name** | **str** |  | [optional] 
+**nested_oneof** | [**OneOfBasquePigDanishPig**](OneOfBasquePigDanishPig.md) |  | [optional] 
+
+## Example
+
+```python
+from petstore_api.models.all_of_with_nested_one_of_all_of import AllOfWithNestedOneOfAllOf
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of AllOfWithNestedOneOfAllOf from a JSON string
+all_of_with_nested_one_of_all_of_instance = AllOfWithNestedOneOfAllOf.from_json(json)
+# print the JSON string representation of the object
+print AllOfWithNestedOneOfAllOf.to_json()
+
+# convert the object into a dict
+all_of_with_nested_one_of_all_of_dict = all_of_with_nested_one_of_all_of_instance.to_dict()
+# create an instance of AllOfWithNestedOneOfAllOf from a dict
+all_of_with_nested_one_of_all_of_form_dict = all_of_with_nested_one_of_all_of.from_dict(all_of_with_nested_one_of_all_of_dict)
+```
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/openapi3/client/petstore/python-nextgen/petstore_api/__init__.py b/samples/openapi3/client/petstore/python-nextgen/petstore_api/__init__.py
index ff667b0dd14..e682cbad7d1 100755
--- a/samples/openapi3/client/petstore/python-nextgen/petstore_api/__init__.py
+++ b/samples/openapi3/client/petstore/python-nextgen/petstore_api/__init__.py
@@ -36,6 +36,8 @@ from petstore_api.exceptions import ApiAttributeError
 from petstore_api.exceptions import ApiException
 # import models into sdk package
 from petstore_api.models.additional_properties_class import AdditionalPropertiesClass
+from petstore_api.models.all_of_with_nested_one_of import AllOfWithNestedOneOf
+from petstore_api.models.all_of_with_nested_one_of_all_of import AllOfWithNestedOneOfAllOf
 from petstore_api.models.all_of_with_single_ref import AllOfWithSingleRef
 from petstore_api.models.animal import Animal
 from petstore_api.models.any_of_color import AnyOfColor
diff --git a/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/__init__.py b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/__init__.py
index 47c33519b11..638525ce0ab 100644
--- a/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/__init__.py
+++ b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/__init__.py
@@ -15,6 +15,8 @@ from __future__ import absolute_import
 
 # import models into model package
 from petstore_api.models.additional_properties_class import AdditionalPropertiesClass
+from petstore_api.models.all_of_with_nested_one_of import AllOfWithNestedOneOf
+from petstore_api.models.all_of_with_nested_one_of_all_of import AllOfWithNestedOneOfAllOf
 from petstore_api.models.all_of_with_single_ref import AllOfWithSingleRef
 from petstore_api.models.animal import Animal
 from petstore_api.models.any_of_color import AnyOfColor
diff --git a/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of.py b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of.py
new file mode 100644
index 00000000000..ee78b59e144
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of.py
@@ -0,0 +1,95 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+
+from __future__ import annotations
+from inspect import getfullargspec
+import pprint
+import re  # noqa: F401
+import json
+
+
+from typing import Any, Optional
+from pydantic import BaseModel, StrictInt, StrictStr
+
+class AllOfWithNestedOneOf(BaseModel):
+    """NOTE: This class is auto generated by OpenAPI Generator.
+    Ref: https://openapi-generator.tech
+
+    Do not edit the class manually.
+    """
+    id: Optional[StrictInt] = None
+    name: Optional[StrictStr] = None
+    inner_name: Optional[StrictStr] = None
+    nested_oneof: Optional[Any] = None
+    additional_properties: Dict[str, Any] = {}
+    __properties = ["id", "name", "inner_name", "nested_oneof"]
+
+    class Config:
+        allow_population_by_field_name = True
+        validate_assignment = True
+
+    def to_str(self) -> str:
+        """Returns the string representation of the model using alias"""
+        return pprint.pformat(self.dict(by_alias=True))
+
+    def to_json(self) -> str:
+        """Returns the JSON representation of the model using alias"""
+        return json.dumps(self.to_dict())
+
+    @classmethod
+    def from_json(cls, json_str: str) -> AllOfWithNestedOneOf:
+        """Create an instance of AllOfWithNestedOneOf from a JSON string"""
+        return cls.from_dict(json.loads(json_str))
+
+    def to_dict(self):
+        """Returns the dictionary representation of the model using alias"""
+        _dict = self.dict(by_alias=True,
+                          exclude={
+                            "additional_properties"
+                          },
+                          exclude_none=True)
+        # override the default output from pydantic by calling `to_dict()` of nested_oneof
+        if self.nested_oneof:
+            _dict['nested_oneof'] = self.nested_oneof.to_dict()
+        # puts key-value pairs in additional_properties in the top level
+        if self.additional_properties is not None:
+            for _key, _value in self.additional_properties.items():
+                _dict[_key] = _value
+
+        # set to None if nested_oneof (nullable) is None
+        if self.nested_oneof is None:
+            _dict['nested_oneof'] = None
+
+        return _dict
+
+    @classmethod
+    def from_dict(cls, obj: dict) -> AllOfWithNestedOneOf:
+        """Create an instance of AllOfWithNestedOneOf from a dict"""
+        if obj is None:
+            return None
+
+        if type(obj) is not dict:
+            return AllOfWithNestedOneOf.parse_obj(obj)
+
+        _obj = AllOfWithNestedOneOf.parse_obj({
+            "id": obj.get("id"),
+            "name": obj.get("name"),
+            "inner_name": obj.get("inner_name"),
+            "nested_oneof": OneOfBasquePigDanishPig.from_dict(obj.get("nested_oneof")) if obj.get("nested_oneof") is not None else None
+        })
+        # store additional fields in additional_properties
+        for _key in obj.keys():
+            if _key not in cls.__properties:
+                _obj.additional_properties[_key] = obj.get(_key)
+
+        return _obj
+
diff --git a/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of_all_of.py b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of_all_of.py
new file mode 100644
index 00000000000..3a9b46606ff
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/petstore_api/models/all_of_with_nested_one_of_all_of.py
@@ -0,0 +1,91 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+
+from __future__ import annotations
+from inspect import getfullargspec
+import pprint
+import re  # noqa: F401
+import json
+
+
+from typing import Any, Optional
+from pydantic import BaseModel, StrictStr
+
+class AllOfWithNestedOneOfAllOf(BaseModel):
+    """NOTE: This class is auto generated by OpenAPI Generator.
+    Ref: https://openapi-generator.tech
+
+    Do not edit the class manually.
+    """
+    inner_name: Optional[StrictStr] = None
+    nested_oneof: Optional[Any] = None
+    additional_properties: Dict[str, Any] = {}
+    __properties = ["inner_name", "nested_oneof"]
+
+    class Config:
+        allow_population_by_field_name = True
+        validate_assignment = True
+
+    def to_str(self) -> str:
+        """Returns the string representation of the model using alias"""
+        return pprint.pformat(self.dict(by_alias=True))
+
+    def to_json(self) -> str:
+        """Returns the JSON representation of the model using alias"""
+        return json.dumps(self.to_dict())
+
+    @classmethod
+    def from_json(cls, json_str: str) -> AllOfWithNestedOneOfAllOf:
+        """Create an instance of AllOfWithNestedOneOfAllOf from a JSON string"""
+        return cls.from_dict(json.loads(json_str))
+
+    def to_dict(self):
+        """Returns the dictionary representation of the model using alias"""
+        _dict = self.dict(by_alias=True,
+                          exclude={
+                            "additional_properties"
+                          },
+                          exclude_none=True)
+        # override the default output from pydantic by calling `to_dict()` of nested_oneof
+        if self.nested_oneof:
+            _dict['nested_oneof'] = self.nested_oneof.to_dict()
+        # puts key-value pairs in additional_properties in the top level
+        if self.additional_properties is not None:
+            for _key, _value in self.additional_properties.items():
+                _dict[_key] = _value
+
+        # set to None if nested_oneof (nullable) is None
+        if self.nested_oneof is None:
+            _dict['nested_oneof'] = None
+
+        return _dict
+
+    @classmethod
+    def from_dict(cls, obj: dict) -> AllOfWithNestedOneOfAllOf:
+        """Create an instance of AllOfWithNestedOneOfAllOf from a dict"""
+        if obj is None:
+            return None
+
+        if type(obj) is not dict:
+            return AllOfWithNestedOneOfAllOf.parse_obj(obj)
+
+        _obj = AllOfWithNestedOneOfAllOf.parse_obj({
+            "inner_name": obj.get("inner_name"),
+            "nested_oneof": OneOfBasquePigDanishPig.from_dict(obj.get("nested_oneof")) if obj.get("nested_oneof") is not None else None
+        })
+        # store additional fields in additional_properties
+        for _key in obj.keys():
+            if _key not in cls.__properties:
+                _obj.additional_properties[_key] = obj.get(_key)
+
+        return _obj
+
diff --git a/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of.py b/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of.py
new file mode 100644
index 00000000000..9dd77019fdf
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of.py
@@ -0,0 +1,56 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+
+from __future__ import absolute_import
+
+import unittest
+import datetime
+
+import petstore_api
+from petstore_api.models.all_of_with_nested_one_of import AllOfWithNestedOneOf  # noqa: E501
+from petstore_api.rest import ApiException
+
+class TestAllOfWithNestedOneOf(unittest.TestCase):
+    """AllOfWithNestedOneOf unit test stubs"""
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def make_instance(self, include_optional):
+        """Test AllOfWithNestedOneOf
+            include_option is a boolean, when False only required
+            params are included, when True both required and
+            optional params are included """
+        # uncomment below to create an instance of `AllOfWithNestedOneOf`
+        """
+        model = petstore_api.models.all_of_with_nested_one_of.AllOfWithNestedOneOf()  # noqa: E501
+        if include_optional :
+            return AllOfWithNestedOneOf(
+                id = 56, 
+                name = None, 
+                nested_oneof = None
+            )
+        else :
+            return AllOfWithNestedOneOf(
+        )
+        """
+
+    def testAllOfWithNestedOneOf(self):
+        """Test AllOfWithNestedOneOf"""
+        # inst_req_only = self.make_instance(include_optional=False)
+        # inst_req_and_optional = self.make_instance(include_optional=True)
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of_all_of.py b/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of_all_of.py
new file mode 100644
index 00000000000..fb0180046bb
--- /dev/null
+++ b/samples/openapi3/client/petstore/python-nextgen/test/test_all_of_with_nested_one_of_all_of.py
@@ -0,0 +1,55 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    The version of the OpenAPI document: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+
+from __future__ import absolute_import
+
+import unittest
+import datetime
+
+import petstore_api
+from petstore_api.models.all_of_with_nested_one_of_all_of import AllOfWithNestedOneOfAllOf  # noqa: E501
+from petstore_api.rest import ApiException
+
+class TestAllOfWithNestedOneOfAllOf(unittest.TestCase):
+    """AllOfWithNestedOneOfAllOf unit test stubs"""
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def make_instance(self, include_optional):
+        """Test AllOfWithNestedOneOfAllOf
+            include_option is a boolean, when False only required
+            params are included, when True both required and
+            optional params are included """
+        # uncomment below to create an instance of `AllOfWithNestedOneOfAllOf`
+        """
+        model = petstore_api.models.all_of_with_nested_one_of_all_of.AllOfWithNestedOneOfAllOf()  # noqa: E501
+        if include_optional :
+            return AllOfWithNestedOneOfAllOf(
+                name = None, 
+                nested_oneof = None
+            )
+        else :
+            return AllOfWithNestedOneOfAllOf(
+        )
+        """
+
+    def testAllOfWithNestedOneOfAllOf(self):
+        """Test AllOfWithNestedOneOfAllOf"""
+        # inst_req_only = self.make_instance(include_optional=False)
+        # inst_req_and_optional = self.make_instance(include_optional=True)
+
+if __name__ == '__main__':
+    unittest.main()