diff --git a/apispec/core.py b/apispec/core.py
index 332285db..a6c6f61d 100644
--- a/apispec/core.py
+++ b/apispec/core.py
@@ -156,15 +156,26 @@ def to_dict(self):
             ret['swagger'] = self.openapi_version.vstring
             ret['definitions'] = self._definitions
             ret['parameters'] = self._parameters
+            ret.update(self.options)
 
         elif self.openapi_version.version[0] == 3:
             ret['openapi'] = self.openapi_version.vstring
-            ret['components'] = {
-                'schemas': self._definitions,
-                'parameters': self._parameters,
-            }
+            options = self.options.copy()
+            components = options.pop('components', {})
+
+            # deep update components object
+            definitions = components.pop('schemas', {})
+            definitions.update(self._definitions)
+            parameters = components.pop('parameters', {})
+            parameters.update(self._parameters)
+
+            ret['components'] = dict(
+                schemas=definitions,
+                parameters=parameters,
+                **components
+            )
+            ret.update(options)
 
-        ret.update(self.options)
         return ret
 
     def to_yaml(self):
diff --git a/tests/test_core.py b/tests/test_core.py
index e0d6527b..c91d98c2 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -26,11 +26,28 @@ def spec():
 
 @pytest.fixture()
 def spec_3():
+    components = {
+        'securitySchemes': {
+            'bearerAuth':
+                dict(type='http', scheme='bearer', bearerFormat='JWT')
+        },
+        'schemas': {
+            'ErrorResponse': {
+                'type': 'object',
+                'properties': {
+                    'ok': {
+                        'type': 'boolean', 'description': 'status indicator', 'example': False
+                    }
+                },
+                'required': ['ok']
+            }
+        }
+    }
     return APISpec(
         title='Swagger Petstore',
         version='1.0.0',
         info={'description': description},
-        security=[{'apiKey': []}],
+        components=components,
         openapi_version='3.0.0'
     )
 
@@ -64,6 +81,26 @@ def test_swagger_metadata(self, spec):
         assert metadata['info']['version'] == '1.0.0'
         assert metadata['info']['description'] == description
 
+    def test_swagger_metadata_v3(self, spec_3):
+        metadata = spec_3.to_dict()
+        security_schemes = {'bearerAuth': dict(type='http', scheme='bearer', bearerFormat='JWT')}
+        assert metadata['components']['securitySchemes'] == security_schemes
+        assert metadata['components']['schemas'].get('ErrorResponse', False)
+        assert metadata['info']['title'] == 'Swagger Petstore'
+        assert metadata['info']['version'] == '1.0.0'
+        assert metadata['info']['description'] == description
+
+    def test_swagger_metadata_merge_v3(self, spec_3):
+        properties = {
+            'ok': {
+                'type': 'boolean', 'description': 'property description', 'example': True
+            }
+        }
+        spec_3.definition('definition', properties=properties, description='definiton description')
+        metadata = spec_3.to_dict()
+        assert metadata['components']['schemas'].get('ErrorResponse', False)
+        assert metadata['components']['schemas'].get('definition', False)
+
 
 class TestTags: