diff --git a/.rspec b/.rspec
index c2e29743..de4044ae 100644
--- a/.rspec
+++ b/.rspec
@@ -1,3 +1,4 @@
 --color
 --profile
 --format documentation
+--require 'spec_helper'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b98063cc..aa559f7e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 * [#958](https://github.com/ruby-grape/grape-swagger/pull/958): Drop ruby-head from test matrix - [@numbata](https://github.com/numbata).
 * [#953](https://github.com/ruby-grape/grape-swagger/pull/953): Added `super_diff` - [@numbata](https://github.com/numbata).
 * [#951](https://github.com/ruby-grape/grape-swagger/pull/951): Use `x-example` for non-body parameters - [@olivier-thatch](https://github.com/olivier-thatch).
+* [#963](https://github.com/ruby-grape/grape-swagger/pull/963): Allow empty model definitions for swagger 2.0 - [@numbata](https://github.com/numbata).
 * Your contribution here.
 
 #### Fixes
diff --git a/Gemfile b/Gemfile
index 9cfcb559..66255fc2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-source 'http://rubygems.org'
+source 'https://rubygems.org'
 
 gemspec
 
diff --git a/lib/grape-swagger/doc_methods/build_model_definition.rb b/lib/grape-swagger/doc_methods/build_model_definition.rb
index 444b17f8..864d4471 100644
--- a/lib/grape-swagger/doc_methods/build_model_definition.rb
+++ b/lib/grape-swagger/doc_methods/build_model_definition.rb
@@ -22,7 +22,7 @@ def parse_params_from_model(parsed_response, model, model_name)
             }
           else
             properties, required = parsed_response
-            unless properties&.any?
+            if properties.nil?
               raise GrapeSwagger::Errors::SwaggerSpec,
                     "Empty model #{model_name}, swagger 2.0 doesn't support empty definitions."
             end
diff --git a/spec/issues/539_array_post_body_spec.rb b/spec/issues/539_array_post_body_spec.rb
index 0bf43eca..2476db74 100644
--- a/spec/issues/539_array_post_body_spec.rb
+++ b/spec/issues/539_array_post_body_spec.rb
@@ -74,7 +74,8 @@ class ArrayOfElements < Grape::Entity
           'id' => { 'type' => 'string' },
           'description' => { 'type' => 'string' },
           'role' => { 'type' => 'string' }
-        }
+        },
+        'required' => %w[id description role]
       }
     )
   end
diff --git a/spec/issues/962_polymorphic_entity_with_custom_documentation_spec.rb b/spec/issues/962_polymorphic_entity_with_custom_documentation_spec.rb
new file mode 100644
index 00000000..46f6237e
--- /dev/null
+++ b/spec/issues/962_polymorphic_entity_with_custom_documentation_spec.rb
@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+
+describe '#962 polymorphic entity with custom documentation' do
+  let(:app) do
+    Class.new(Grape::API) do
+      namespace :issue_962 do
+        module Issue962
+          class EmptyEntity < Grape::Entity
+          end
+
+          class EntityWithHiddenProperty < Grape::Entity
+            expose :hidden_prop, documentation: { hidden: true, desc: 'This property is not exposed.' }
+          end
+
+          class EntityWithNestedEmptyEntity < Grape::Entity
+            expose :array_of_empty_entities,
+                   as: :empty_items,
+                   using: Issue962::EmptyEntity,
+                   documentation: {
+                     is_array: true,
+                     desc: 'This is a nested empty entity.'
+                   }
+            expose :array_of_hidden_entities,
+                   as: :hidden_items,
+                   using: Issue962::EntityWithHiddenProperty,
+                   documentation: {
+                     is_array: true,
+                     desc: 'This is a nested entity with hidden props'
+                   }
+          end
+        end
+
+        desc 'Get a report',
+             success: Issue962::EntityWithNestedEmptyEntity
+        get '/' do
+          present({ foo: [] }, with: Issue962::EntityWithNestedEmptyEntity)
+        end
+      end
+
+      add_swagger_documentation format: :json
+    end
+  end
+
+  subject do
+    get '/swagger_doc'
+    JSON.parse(last_response.body)
+  end
+
+  let(:definitions) { subject['definitions'] }
+  let(:entity_definition) { definitions['Issue962_EntityWithNestedEmptyEntity'] }
+  let(:empty_items_property) { entity_definition['properties']['empty_items'] }
+  let(:hidden_items_property) { entity_definition['properties']['hidden_items'] }
+  let(:empty_entity_definition) { definitions['Issue962_EmptyEntity'] }
+  let(:hidden_entity_definition) { definitions['Issue962_EntityWithHiddenProperty'] }
+
+  specify 'should generate swagger documentation without error' do
+    expect { subject }.not_to raise_error
+  end
+
+  specify do
+    expect(definitions.keys).to include(
+      'Issue962_EntityWithNestedEmptyEntity',
+      'Issue962_EntityWithHiddenProperty',
+      'Issue962_EmptyEntity'
+    )
+  end
+
+  specify do
+    expect(empty_items_property).to eql({
+      'type' => 'array',
+      'description' => 'This is a nested empty entity.',
+      'items' => {
+        '$ref' => '#/definitions/Issue962_EmptyEntity'
+      }
+    })
+  end
+
+  specify do
+    expect(hidden_items_property).to eql({
+      'type' => 'array',
+      'description' => 'This is a nested entity with hidden props',
+      'items' => {
+        '$ref' => '#/definitions/Issue962_EntityWithHiddenProperty'
+      }
+    })
+  end
+
+  specify do
+    expect(empty_entity_definition).to eql({
+      'type' => 'object',
+      'properties' => {}
+    })
+  end
+
+  specify do
+    expect(hidden_entity_definition).to eql({
+      'type' => 'object',
+      'properties' => {},
+      'required' => ['hidden_prop']
+    })
+  end
+
+  let(:response_schema) { subject['paths']['/issue_962']['get']['responses']['200']['schema'] }
+
+  specify do
+    expect(response_schema).to eql({
+      '$ref' => '#/definitions/Issue962_EntityWithNestedEmptyEntity'
+    })
+  end
+end
diff --git a/spec/support/model_parsers/entity_parser.rb b/spec/support/model_parsers/entity_parser.rb
index 5f2a47e9..a9984d54 100644
--- a/spec/support/model_parsers/entity_parser.rb
+++ b/spec/support/model_parsers/entity_parser.rb
@@ -135,33 +135,44 @@ class DocumentedHashAndArrayModel < Grape::Entity
 
   let(:swagger_definitions_models) do
     {
-      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } } },
-      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } } },
-      'UseResponse' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, '$responses' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/ResponseItem' } } } },
-      'RecursiveModel' => { 'type' => 'object', 'properties' => { 'name' => { 'type' => 'string', 'description' => 'The name.' }, 'children' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/RecursiveModel' }, 'description' => 'The child nodes.' } } },
-      'DocumentedHashAndArrayModel' => { 'type' => 'object', 'properties' => { 'raw_hash' => { 'type' => 'object', 'description' => 'Example Hash.' }, 'raw_array' => { 'type' => 'array', 'description' => 'Example Array' } } }
+      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } }, 'required' => %w[code message] },
+      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } }, 'required' => %w[id name] },
+      'UseResponse' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, '$responses' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/ResponseItem' } } }, 'required' => ['description', '$responses'] },
+      'RecursiveModel' => { 'type' => 'object', 'properties' => { 'name' => { 'type' => 'string', 'description' => 'The name.' }, 'children' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/RecursiveModel' }, 'description' => 'The child nodes.' } }, 'required' => %w[name children] },
+      'DocumentedHashAndArrayModel' => { 'type' => 'object', 'properties' => { 'raw_hash' => { 'type' => 'object', 'description' => 'Example Hash.' }, 'raw_array' => { 'type' => 'array', 'description' => 'Example Array' } }, 'required' => %w[raw_hash raw_array] }
     }
   end
 
   let(:swagger_nested_type) do
     {
-      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } }, 'description' => 'ApiError model' },
-      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } } },
-      'UseItemResponseAsType' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, 'responses' => { '$ref' => '#/definitions/ResponseItem' } }, 'description' => 'UseItemResponseAsType model' }
+      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } }, 'required' => %w[code message], 'description' => 'ApiError model' },
+      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } }, 'required' => %w[id name] },
+      'UseItemResponseAsType' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, 'responses' => { '$ref' => '#/definitions/ResponseItem' } }, 'required' => %w[description responses], 'description' => 'UseItemResponseAsType model' }
     }
   end
 
   let(:swagger_entity_as_response_object) do
     {
-      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } }, 'description' => 'ApiError model' },
-      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } } },
-      'UseResponse' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, '$responses' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/ResponseItem' } } }, 'description' => 'UseResponse model' }
+      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } }, 'required' => %w[code message], 'description' => 'ApiError model' },
+      'ResponseItem' => { 'type' => 'object', 'properties' => { 'id' => { 'type' => 'integer', 'format' => 'int32' }, 'name' => { 'type' => 'string' } }, 'required' => %w[id name] },
+      'UseResponse' => { 'type' => 'object', 'properties' => { 'description' => { 'type' => 'string' }, '$responses' => { 'type' => 'array', 'items' => { '$ref' => '#/definitions/ResponseItem' } } }, 'required' => ['description', '$responses'], 'description' => 'UseResponse model' }
     }
   end
 
   let(:swagger_params_as_response_object) do
     {
-      'ApiError' => { 'type' => 'object', 'properties' => { 'code' => { 'description' => 'status code', 'type' => 'integer', 'format' => 'int32' }, 'message' => { 'description' => 'error message', 'type' => 'string' } }, 'description' => 'ApiError model' }
+      'ApiError' => {
+        'type' => 'object',
+        'properties' => {
+          'code' => { 'description' => 'status code', 'type' => 'integer', 'format' => 'int32' },
+          'message' => { 'description' => 'error message', 'type' => 'string' }
+        },
+        'required' => %w[
+          code
+          message
+        ],
+        'description' => 'ApiError model'
+      }
     }
   end
 
@@ -310,6 +321,7 @@ class DocumentedHashAndArrayModel < Grape::Entity
         'ApiError' => {
           'type' => 'object',
           'properties' => { 'code' => { 'type' => 'integer', 'format' => 'int32', 'description' => 'status code' }, 'message' => { 'type' => 'string', 'description' => 'error message' } },
+          'required' => %w[code message],
           'description' => 'ApiError model'
         },
         'Something' => {
@@ -320,6 +332,7 @@ class DocumentedHashAndArrayModel < Grape::Entity
             'links' => { 'type' => 'array', 'items' => { 'type' => 'link' } },
             'others' => { 'type' => 'text' }
           },
+          'required' => %w[id text links others],
           'description' => 'Something model'
         }
       }
diff --git a/spec/swagger_v2/errors_spec.rb b/spec/swagger_v2/errors_spec.rb
index f42eae43..957de022 100644
--- a/spec/swagger_v2/errors_spec.rb
+++ b/spec/swagger_v2/errors_spec.rb
@@ -34,8 +34,8 @@
       end
     end
 
-    it 'should raise SwaggerSpec exception' do
-      expect { get '/v3/swagger_doc' }.to raise_error(GrapeSwagger::Errors::SwaggerSpec, "Empty model EmptyClass, swagger 2.0 doesn't support empty definitions.")
+    it 'should not raise SwaggerSpec exception' do
+      expect { get '/v3/swagger_doc' }.not_to raise_error(GrapeSwagger::Errors::SwaggerSpec)
     end
   end
 
diff --git a/spec/swagger_v2/reference_entity_spec.rb b/spec/swagger_v2/reference_entity_spec.rb
index ab7ae247..834dc85e 100644
--- a/spec/swagger_v2/reference_entity_spec.rb
+++ b/spec/swagger_v2/reference_entity_spec.rb
@@ -90,7 +90,9 @@ def app
 
       expect(subject['definitions'].keys).to include 'SomethingCustom'
       expect(subject['definitions']['SomethingCustom']).to eq(
-        'type' => 'object', 'properties' => { 'text' => { 'type' => 'string', 'description' => 'Content of something.' } }
+        'type' => 'object',
+        'properties' => { 'text' => { 'type' => 'string', 'description' => 'Content of something.' } },
+        'required' => ['text']
       )
 
       expect(subject['definitions'].keys).to include 'KindCustom'
@@ -103,6 +105,7 @@ def app
             'description' => 'Something interesting.'
           }
         },
+        'required' => %w[title something],
         'description' => 'KindCustom model'
       )
     end
@@ -122,6 +125,7 @@ def app
           'title' => { 'type' => 'string', 'description' => 'Title of the parent.' },
           'child' => { 'type' => 'string', 'description' => 'Child property.' }
         },
+        'required' => %w[title child],
         'description' => 'MyAPI::Child model'
       )
     end