diff --git a/openapi_core/schema/components/factories.py b/openapi_core/schema/components/factories.py
index 053f099..6afab0a 100644
--- a/openapi_core/schema/components/factories.py
+++ b/openapi_core/schema/components/factories.py
@@ -1,5 +1,6 @@
 from openapi_core.compat import lru_cache
 from openapi_core.schema.components.models import Components
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.schemas.generators import SchemasGenerator
 from openapi_core.schema.security_schemes.generators import (
     SecuritySchemesGenerator,
@@ -21,6 +22,8 @@ class ComponentsFactory(object):
         request_bodies_spec = components_deref.get('requestBodies', {})
         security_schemes_spec = components_deref.get('securitySchemes', {})
 
+        extensions = self.extensions_generator.generate(components_deref)
+
         schemas = self.schemas_generator.generate(schemas_spec)
         responses = self._generate_response(responses_spec)
         parameters = self._generate_parameters(parameters_spec)
@@ -30,6 +33,7 @@ class ComponentsFactory(object):
         return Components(
             schemas=list(schemas), responses=responses, parameters=parameters,
             request_bodies=request_bodies, security_schemes=security_schemes,
+            extensions=extensions,
         )
 
     @property
@@ -37,6 +41,11 @@ class ComponentsFactory(object):
     def schemas_generator(self):
         return SchemasGenerator(self.dereferencer, self.schemas_registry)
 
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
+
     def _generate_response(self, responses_spec):
         return responses_spec
 
diff --git a/openapi_core/schema/components/models.py b/openapi_core/schema/components/models.py
index ee9312f..11a605b 100644
--- a/openapi_core/schema/components/models.py
+++ b/openapi_core/schema/components/models.py
@@ -3,7 +3,7 @@ class Components(object):
 
     def __init__(
             self, schemas=None, responses=None, parameters=None,
-            request_bodies=None, security_schemes=None):
+            request_bodies=None, security_schemes=None, extensions=None):
         self.schemas = schemas and dict(schemas) or {}
         self.responses = responses and dict(responses) or {}
         self.parameters = parameters and dict(parameters) or {}
@@ -11,3 +11,5 @@ class Components(object):
         self.security_schemes = (
             security_schemes and dict(security_schemes) or {}
         )
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/contacts/factories.py b/openapi_core/schema/contacts/factories.py
index cec1b3d..d1724d9 100644
--- a/openapi_core/schema/contacts/factories.py
+++ b/openapi_core/schema/contacts/factories.py
@@ -1,5 +1,7 @@
 """OpenAPI core contacts factories module"""
+from openapi_core.compat import lru_cache
 from openapi_core.schema.contacts.models import Contact
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 
 
 class ContactFactory(object):
@@ -12,4 +14,12 @@ class ContactFactory(object):
         name = contact_deref.get('name')
         url = contact_deref.get('url')
         email = contact_deref.get('email')
-        return Contact(name=name, url=url, email=email)
+
+        extensions = self.extensions_generator.generate(contact_deref)
+
+        return Contact(name=name, url=url, email=email, extensions=extensions)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/contacts/models.py b/openapi_core/schema/contacts/models.py
index 4c2328e..9e5bb2a 100644
--- a/openapi_core/schema/contacts/models.py
+++ b/openapi_core/schema/contacts/models.py
@@ -3,7 +3,9 @@
 
 class Contact(object):
 
-    def __init__(self, name=None, url=None, email=None):
+    def __init__(self, name=None, url=None, email=None, extensions=None):
         self.name = name
         self.url = url
         self.email = email
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/external_docs/factories.py b/openapi_core/schema/external_docs/factories.py
index a2a3900..a1ef10b 100644
--- a/openapi_core/schema/external_docs/factories.py
+++ b/openapi_core/schema/external_docs/factories.py
@@ -1,4 +1,6 @@
 """OpenAPI core external docs factories module"""
+from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.external_docs.models import ExternalDocumentation
 
 
@@ -11,4 +13,14 @@ class ExternalDocumentationFactory(object):
         url = external_doc_spec['url']
         description = external_doc_spec.get('description')
 
-        return ExternalDocumentation(url, description=description)
+        extensions = self.extensions_generator.generate(external_doc_spec)
+
+        return ExternalDocumentation(
+            url,
+            description=description, extensions=extensions,
+        )
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/external_docs/models.py b/openapi_core/schema/external_docs/models.py
index e44cd8b..b0d0a0e 100644
--- a/openapi_core/schema/external_docs/models.py
+++ b/openapi_core/schema/external_docs/models.py
@@ -4,6 +4,8 @@
 class ExternalDocumentation(object):
     """Represents an OpenAPI External Documentation."""
 
-    def __init__(self, url, description=None):
+    def __init__(self, url, description=None, extensions=None):
         self.url = url
         self.description = description
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/infos/factories.py b/openapi_core/schema/infos/factories.py
index 74b0189..20b8b60 100644
--- a/openapi_core/schema/infos/factories.py
+++ b/openapi_core/schema/infos/factories.py
@@ -1,6 +1,7 @@
 """OpenAPI core infos factories module"""
 from openapi_core.compat import lru_cache
 from openapi_core.schema.contacts.factories import ContactFactory
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.infos.models import Info
 from openapi_core.schema.licenses.factories import LicenseFactory
 
@@ -17,6 +18,8 @@ class InfoFactory(object):
         description = info_deref.get('description')
         terms_of_service = info_deref.get('termsOfService')
 
+        extensions = self.extensions_generator.generate(info_deref)
+
         contact = None
         if 'contact' in info_deref:
             contact_spec = info_deref.get('contact')
@@ -30,7 +33,7 @@ class InfoFactory(object):
         return Info(
             title, version,
             description=description, terms_of_service=terms_of_service,
-            contact=contact, license=license,
+            contact=contact, license=license, extensions=extensions,
         )
 
     @property
@@ -42,3 +45,8 @@ class InfoFactory(object):
     @lru_cache()
     def license_factory(self):
         return LicenseFactory(self.dereferencer)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/infos/models.py b/openapi_core/schema/infos/models.py
index 18aebbd..9ccd66a 100644
--- a/openapi_core/schema/infos/models.py
+++ b/openapi_core/schema/infos/models.py
@@ -5,7 +5,7 @@ class Info(object):
 
     def __init__(
             self, title, version, description=None, terms_of_service=None,
-            contact=None, license=None,
+            contact=None, license=None, extensions=None,
     ):
         self.title = title
         self.version = version
@@ -13,3 +13,5 @@ class Info(object):
         self.terms_of_service = terms_of_service
         self.contact = contact
         self.license = license
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/licenses/factories.py b/openapi_core/schema/licenses/factories.py
index 886386f..294babe 100644
--- a/openapi_core/schema/licenses/factories.py
+++ b/openapi_core/schema/licenses/factories.py
@@ -1,4 +1,6 @@
 """OpenAPI core licenses factories module"""
+from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.licenses.models import License
 
 
@@ -11,4 +13,12 @@ class LicenseFactory(object):
         license_deref = self.dereferencer.dereference(license_spec)
         name = license_deref['name']
         url = license_deref.get('url')
-        return License(name, url=url)
+
+        extensions = self.extensions_generator.generate(license_deref)
+
+        return License(name, url=url, extensions=extensions)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/licenses/models.py b/openapi_core/schema/licenses/models.py
index 939eb17..c6dd506 100644
--- a/openapi_core/schema/licenses/models.py
+++ b/openapi_core/schema/licenses/models.py
@@ -3,6 +3,8 @@
 
 class License(object):
 
-    def __init__(self, name, url=None):
+    def __init__(self, name, url=None, extensions=None):
         self.name = name
         self.url = url
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/media_types/generators.py b/openapi_core/schema/media_types/generators.py
index 3eceffb..dcaff53 100644
--- a/openapi_core/schema/media_types/generators.py
+++ b/openapi_core/schema/media_types/generators.py
@@ -1,6 +1,8 @@
 """OpenAPI core media types generators module"""
 from six import iteritems
 
+from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.media_types.models import MediaType
 
 
@@ -21,8 +23,18 @@ class MediaTypeGenerator(object):
             else:
                 example = example_spec
 
+            extensions = self.extensions_generator.generate(media_type)
+
             schema = None
             if schema_spec:
                 schema, _ = self.schemas_registry.get_or_create(schema_spec)
 
-            yield mimetype, MediaType(mimetype, schema=schema, example=example)
+            yield mimetype, MediaType(
+                mimetype,
+                schema=schema, example=example, extensions=extensions,
+            )
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/media_types/models.py b/openapi_core/schema/media_types/models.py
index fc29853..76079f7 100644
--- a/openapi_core/schema/media_types/models.py
+++ b/openapi_core/schema/media_types/models.py
@@ -4,7 +4,9 @@
 class MediaType(object):
     """Represents an OpenAPI MediaType."""
 
-    def __init__(self, mimetype, schema=None, example=None):
+    def __init__(self, mimetype, schema=None, example=None, extensions=None):
         self.mimetype = mimetype
         self.schema = schema
         self.example = example
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/operations/generators.py b/openapi_core/schema/operations/generators.py
index 07b7ba4..c149856 100644
--- a/openapi_core/schema/operations/generators.py
+++ b/openapi_core/schema/operations/generators.py
@@ -4,6 +4,7 @@ from six import iteritems
 from openapi_spec_validator.validators import PathItemValidator
 
 from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.external_docs.factories import (
     ExternalDocumentationFactory,
 )
@@ -47,6 +48,7 @@ class OperationsGenerator(object):
             servers = self.servers_generator.generate(servers_spec)
             security = self.security_requirements_generator.generate(
                 security_spec)
+            extensions = self.extensions_generator.generate(operation_deref)
 
             external_docs = None
             if 'externalDocs' in operation_deref:
@@ -68,7 +70,7 @@ class OperationsGenerator(object):
                     external_docs=external_docs, security=list(security),
                     request_body=request_body, deprecated=deprecated,
                     operation_id=operation_id, tags=list(tags_list),
-                    servers=list(servers),
+                    servers=list(servers), extensions=extensions,
                 ),
             )
 
@@ -101,3 +103,8 @@ class OperationsGenerator(object):
     @lru_cache()
     def servers_generator(self):
         return ServersGenerator(self.dereferencer)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/operations/models.py b/openapi_core/schema/operations/models.py
index 7da4ef3..f7bc773 100644
--- a/openapi_core/schema/operations/models.py
+++ b/openapi_core/schema/operations/models.py
@@ -10,7 +10,7 @@ class Operation(object):
             self, http_method, path_name, responses, parameters,
             summary=None, description=None, external_docs=None, security=None,
             request_body=None, deprecated=False, operation_id=None, tags=None,
-            servers=None):
+            servers=None, extensions=None):
         self.http_method = http_method
         self.path_name = path_name
         self.responses = dict(responses)
@@ -25,6 +25,8 @@ class Operation(object):
         self.tags = tags
         self.servers = servers
 
+        self.extensions = extensions and dict(extensions) or {}
+
     def __getitem__(self, name):
         return self.parameters[name]
 
diff --git a/openapi_core/schema/paths/generators.py b/openapi_core/schema/paths/generators.py
index cc85164..82809f2 100644
--- a/openapi_core/schema/paths/generators.py
+++ b/openapi_core/schema/paths/generators.py
@@ -2,6 +2,7 @@
 from six import iteritems
 
 from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.operations.generators import OperationsGenerator
 from openapi_core.schema.parameters.generators import ParametersGenerator
 from openapi_core.schema.paths.models import Path
@@ -29,12 +30,14 @@ class PathsGenerator(object):
             servers = self.servers_generator.generate(servers_spec)
             parameters = self.parameters_generator.generate_from_list(
                 parameters_list)
+            extensions = self.extensions_generator.generate(path_deref)
+
             yield (
                 path_name,
                 Path(
                     path_name, list(operations), parameters=list(parameters),
                     summary=summary, description=description,
-                    servers=list(servers),
+                    servers=list(servers), extensions=extensions,
                 ),
             )
 
@@ -52,3 +55,8 @@ class PathsGenerator(object):
     @lru_cache()
     def parameters_generator(self):
         return ParametersGenerator(self.dereferencer, self.schemas_registry)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/paths/models.py b/openapi_core/schema/paths/models.py
index 9b6f5b0..74a57a9 100644
--- a/openapi_core/schema/paths/models.py
+++ b/openapi_core/schema/paths/models.py
@@ -7,6 +7,7 @@ class Path(object):
     def __init__(
             self, name, operations,
             summary=None, description=None, parameters=None, servers=None,
+            extensions=None,
     ):
         self.name = name
         self.operations = dict(operations)
@@ -15,5 +16,7 @@ class Path(object):
         self.servers = servers
         self.parameters = dict(parameters) if parameters else {}
 
+        self.extensions = extensions and dict(extensions) or {}
+
     def __getitem__(self, http_method):
         return self.operations[http_method]
diff --git a/openapi_core/schema/request_bodies/factories.py b/openapi_core/schema/request_bodies/factories.py
index ba659a3..a8a756e 100644
--- a/openapi_core/schema/request_bodies/factories.py
+++ b/openapi_core/schema/request_bodies/factories.py
@@ -1,5 +1,6 @@
 """OpenAPI core request bodies factories module"""
 from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.media_types.generators import MediaTypeGenerator
 from openapi_core.schema.request_bodies.models import RequestBody
 
@@ -16,9 +17,20 @@ class RequestBodyFactory(object):
         content = request_body_deref['content']
         media_types = self.media_types_generator.generate(content)
         required = request_body_deref.get('required', False)
-        return RequestBody(media_types, required=required)
+
+        extensions = self.extensions_generator.generate(request_body_deref)
+
+        return RequestBody(
+            media_types,
+            required=required, extensions=extensions,
+        )
 
     @property
     @lru_cache()
     def media_types_generator(self):
         return MediaTypeGenerator(self.dereferencer, self.schemas_registry)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/request_bodies/models.py b/openapi_core/schema/request_bodies/models.py
index a15c748..925112d 100644
--- a/openapi_core/schema/request_bodies/models.py
+++ b/openapi_core/schema/request_bodies/models.py
@@ -7,10 +7,12 @@ from openapi_core.schema.media_types.exceptions import InvalidContentType
 class RequestBody(object):
     """Represents an OpenAPI RequestBody."""
 
-    def __init__(self, content, required=False):
+    def __init__(self, content, required=False, extensions=None):
         self.content = Content(content)
         self.required = required
 
+        self.extensions = extensions and dict(extensions) or {}
+
     def __getitem__(self, mimetype):
         try:
             return self.content[mimetype]
diff --git a/openapi_core/schema/responses/generators.py b/openapi_core/schema/responses/generators.py
index c207095..f74e152 100644
--- a/openapi_core/schema/responses/generators.py
+++ b/openapi_core/schema/responses/generators.py
@@ -2,6 +2,7 @@
 from six import iteritems
 
 from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.links.generators import LinksGenerator
 from openapi_core.schema.media_types.generators import MediaTypeGenerator
 from openapi_core.schema.parameters.generators import ParametersGenerator
@@ -23,6 +24,8 @@ class ResponsesGenerator(object):
             links_dict = response_deref.get('links', {})
             links = self.links_generator.generate(links_dict)
 
+            extensions = self.extensions_generator.generate(response_deref)
+
             media_types = None
             if content:
                 media_types = self.media_types_generator.generate(content)
@@ -33,7 +36,9 @@ class ResponsesGenerator(object):
 
             yield http_status, Response(
                 http_status, description,
-                content=media_types, headers=parameters, links=links)
+                content=media_types, headers=parameters, links=links,
+                extensions=extensions,
+            )
 
     @property
     @lru_cache()
@@ -49,3 +54,8 @@ class ResponsesGenerator(object):
     @lru_cache()
     def links_generator(self):
         return LinksGenerator(self.dereferencer, self.schemas_registry)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/responses/models.py b/openapi_core/schema/responses/models.py
index 080f60f..21dffc5 100644
--- a/openapi_core/schema/responses/models.py
+++ b/openapi_core/schema/responses/models.py
@@ -8,13 +8,15 @@ class Response(object):
 
     def __init__(
             self, http_status, description, headers=None, content=None,
-            links=None):
+            links=None, extensions=None):
         self.http_status = http_status
         self.description = description
         self.headers = headers and dict(headers) or {}
         self.content = content and Content(content) or Content()
         self.links = links and dict(links) or {}
 
+        self.extensions = extensions and dict(extensions) or {}
+
     def __getitem__(self, mimetype):
         return self.get_content_type(mimetype)
 
diff --git a/openapi_core/schema/servers/generators.py b/openapi_core/schema/servers/generators.py
index c9c41b6..ca8dbc7 100644
--- a/openapi_core/schema/servers/generators.py
+++ b/openapi_core/schema/servers/generators.py
@@ -2,6 +2,7 @@
 from six import iteritems
 
 from openapi_core.compat import lru_cache
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.servers.models import Server, ServerVariable
 
 
@@ -17,17 +18,28 @@ class ServersGenerator(object):
             variables_spec = server_spec.get('variables', {})
             description = server_spec.get('description')
 
+            extensions = self.extensions_generator.generate(server_spec)
+
             variables = None
             if variables_spec:
                 variables = self.variables_generator.generate(variables_spec)
 
-            yield Server(url, variables=variables, description=description)
+            yield Server(
+                url,
+                variables=variables, description=description,
+                extensions=extensions,
+            )
 
     @property
     @lru_cache()
     def variables_generator(self):
         return ServerVariablesGenerator(self.dereferencer)
 
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
+
 
 class ServerVariablesGenerator(object):
 
@@ -41,5 +53,15 @@ class ServerVariablesGenerator(object):
             default = variable_spec['default']
             enum = variable_spec.get('enum')
 
-            variable = ServerVariable(variable_name, default, enum=enum)
+            extensions = self.extensions_generator.generate(variable_spec)
+
+            variable = ServerVariable(
+                variable_name, default,
+                enum=enum, extensions=extensions,
+            )
             yield variable_name, variable
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/servers/models.py b/openapi_core/schema/servers/models.py
index 3620b28..7c4ac9f 100644
--- a/openapi_core/schema/servers/models.py
+++ b/openapi_core/schema/servers/models.py
@@ -5,11 +5,13 @@ from six.moves.urllib.parse import urljoin
 
 class Server(object):
 
-    def __init__(self, url, variables=None, description=None):
+    def __init__(self, url, variables=None, description=None, extensions=None):
         self.url = url
         self.variables = variables and dict(variables) or {}
         self.description = description
 
+        self.extensions = extensions and dict(extensions) or {}
+
     @property
     def default_url(self):
         return self.get_url()
@@ -38,7 +40,9 @@ class Server(object):
 
 class ServerVariable(object):
 
-    def __init__(self, name, default, enum=None):
+    def __init__(self, name, default, enum=None, extensions=None):
         self.name = name
         self.default = default
         self.enum = enum and list(enum) or []
+
+        self.extensions = extensions and dict(extensions) or {}
diff --git a/openapi_core/schema/specs/factories.py b/openapi_core/schema/specs/factories.py
index 592cf04..384ef8e 100644
--- a/openapi_core/schema/specs/factories.py
+++ b/openapi_core/schema/specs/factories.py
@@ -6,6 +6,7 @@ from openapi_spec_validator.validators import Dereferencer
 
 from openapi_core.compat import lru_cache
 from openapi_core.schema.components.factories import ComponentsFactory
+from openapi_core.schema.extensions.generators import ExtensionsGenerator
 from openapi_core.schema.infos.factories import InfoFactory
 from openapi_core.schema.paths.generators import PathsGenerator
 from openapi_core.schema.schemas.registries import SchemaRegistry
@@ -39,6 +40,8 @@ class SpecFactory(object):
                 {'url': '/'},
             ]
 
+        extensions = self.extensions_generator.generate(spec_dict_deref)
+
         info = self.info_factory.create(info_spec)
         servers = self.servers_generator.generate(servers_spec)
         paths = self.paths_generator.generate(paths)
@@ -49,7 +52,7 @@ class SpecFactory(object):
 
         spec = Spec(
             info, list(paths), servers=list(servers), components=components,
-            security=list(security),
+            security=list(security), extensions=extensions,
             _resolver=self.spec_resolver,
         )
         return spec
@@ -88,3 +91,8 @@ class SpecFactory(object):
     @lru_cache()
     def security_requirements_generator(self):
         return SecurityRequirementsGenerator(self.dereferencer)
+
+    @property
+    @lru_cache()
+    def extensions_generator(self):
+        return ExtensionsGenerator(self.dereferencer)
diff --git a/openapi_core/schema/specs/models.py b/openapi_core/schema/specs/models.py
index 7f41b70..6c24ab9 100644
--- a/openapi_core/schema/specs/models.py
+++ b/openapi_core/schema/specs/models.py
@@ -16,13 +16,15 @@ class Spec(object):
 
     def __init__(
             self, info, paths, servers=None, components=None,
-            security=None, _resolver=None):
+            security=None, extensions=None, _resolver=None):
         self.info = info
         self.paths = paths and dict(paths)
         self.servers = servers or []
         self.components = components
         self.security = security
 
+        self.extensions = extensions and dict(extensions) or {}
+
         self._resolver = _resolver
 
     def __getitem__(self, path_pattern):