diff --git a/quantum/api/v2/resource.py b/quantum/api/v2/resource.py
index 97fc8a8ada..bf9bcb132c 100644
--- a/quantum/api/v2/resource.py
+++ b/quantum/api/v2/resource.py
@@ -94,6 +94,17 @@ def Resource(controller, faults=None, deserializers=None, serializers=None):
             e.body = serializer.serialize({'QuantumError': e})
             e.content_type = content_type
             raise
+        except NotImplementedError as e:
+            # NOTE(armando-migliaccio): from a client standpoint
+            # it makes sense to receive these errors, because
+            # extensions may or may not be implemented by
+            # the underlying plugin. So if something goes south,
+            # because a plugin does not implement a feature,
+            # returning 500 is definitely confusing.
+            body = serializer.serialize(
+                {'NotImplementedError': e.message})
+            kwargs = {'body': body, 'content_type': content_type}
+            raise webob.exc.HTTPNotImplemented(**kwargs)
         except Exception as e:
             # NOTE(jkoelker) Everyting else is 500
             LOG.exception(_('%s failed'), action)
diff --git a/quantum/tests/unit/test_extensions.py b/quantum/tests/unit/test_extensions.py
index 3ac43b2b64..a1bd09e5ac 100644
--- a/quantum/tests/unit/test_extensions.py
+++ b/quantum/tests/unit/test_extensions.py
@@ -76,7 +76,7 @@ class ResourceExtensionTest(base.BaseTestCase):
             return {'data': {'id': id}}
 
         def notimplemented_function(self, request, id):
-            return webob.exc.HTTPClientError(NotImplementedError())
+            return webob.exc.HTTPNotImplemented()
 
         def custom_member_action(self, request, id):
             return {'member_action': 'value'}
@@ -114,8 +114,8 @@ class ResourceExtensionTest(base.BaseTestCase):
             test_app.get("/tweedles/some_id/notimplemented_function")
             # Shouldn't be reached
             self.assertTrue(False)
-        except webtest.AppError:
-            pass
+        except webtest.AppError as e:
+            self.assertTrue('501' in e.message)
 
     def test_resource_can_be_added_as_extension(self):
         res_ext = extensions.ResourceExtension(