diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7c3b430e..2816a47f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@
 
 * [#503](https://github.com/ruby-grape/grape-swagger/pull/503): Corrects exposing of inline definitions - [@LeFnord](https://github.com/LeFnord).
 * [#494](https://github.com/ruby-grape/grape-swagger/pull/494): Header parametes are now included in documentation when body parameters have been defined - [@anakinj](https://github.com/anakinj).
+* [#505](https://github.com/ruby-grape/grape-swagger/pull/505): Combines namespaces with their mounted paths to allow APIs with specified mount_paths - [@KevinLiddle](https://github.com/KevinLiddle).
 * Your contribution here.
 
 ### 0.23.0 (August 5, 2016)
diff --git a/lib/grape-swagger.rb b/lib/grape-swagger.rb
index a43f38f4..e3f7813d 100644
--- a/lib/grape-swagger.rb
+++ b/lib/grape-swagger.rb
@@ -86,7 +86,9 @@ def combine_namespaces(app)
                end
           # use the full namespace here (not the latest level only)
           # and strip leading slash
-          @target_class.combined_namespaces[endpoint.namespace.sub(/^\//, '')] = ns if ns
+          mount_path = (endpoint.namespace_stackable(:mount_path) || []).join('/')
+          full_namespace = (mount_path + endpoint.namespace).sub(/\/{2,}/, '/').sub(/^\//, '')
+          @target_class.combined_namespaces[full_namespace] = ns if ns
 
           combine_namespaces(endpoint.options[:app]) if endpoint.options[:app]
         end
diff --git a/spec/swagger_v2/namespaced_api_spec.rb b/spec/swagger_v2/namespaced_api_spec.rb
index ad7fab36..3297a9ec 100644
--- a/spec/swagger_v2/namespaced_api_spec.rb
+++ b/spec/swagger_v2/namespaced_api_spec.rb
@@ -64,4 +64,56 @@ def app
       expect(subject['description']).to eql('Description for aspace')
     end
   end
+
+  context 'mounted under a route' do
+    def app
+      namespaced_api = Class.new(Grape::API) do
+        namespace :bspace do
+          get '/', desc: 'Description for aspace'
+        end
+      end
+
+      Class.new(Grape::API) do
+        mount namespaced_api => '/mounted'
+        add_swagger_documentation format: :json
+      end
+    end
+
+    subject do
+      get '/swagger_doc'
+      JSON.parse(last_response.body)['paths']['/mounted/bspace']['get']
+    end
+
+    it 'shows the namespace description in the json spec' do
+      expect(subject['description']).to eql('Description for aspace')
+    end
+  end
+
+  context 'arbitrary mounting' do
+    def app
+      inner_namespaced_api = Class.new(Grape::API) do
+        namespace :bspace do
+          get '/', desc: 'Description for aspace'
+        end
+      end
+
+      outer_namespaced_api = Class.new(Grape::API) do
+        mount inner_namespaced_api => '/mounted'
+      end
+
+      Class.new(Grape::API) do
+        mount outer_namespaced_api => '/'
+        add_swagger_documentation format: :json
+      end
+    end
+
+    subject do
+      get '/swagger_doc'
+      JSON.parse(last_response.body)['paths']['/mounted/bspace']['get']
+    end
+
+    it 'shows the namespace description in the json spec' do
+      expect(subject['description']).to eql('Description for aspace')
+    end
+  end
 end