diff --git a/rest_framework_json_schema/schema.py b/rest_framework_json_schema/schema.py
index 96b22dd..f83a8ee 100644
--- a/rest_framework_json_schema/schema.py
+++ b/rest_framework_json_schema/schema.py
@@ -119,7 +119,8 @@ def render(self, data, context):
     def render_attributes(self, data, context):
         attributes = self.filter_by_fields(self.attributes, context.fields)
         return OrderedDict(
-            (self.transformed_names[attr], self.from_data(data, attr)) for attr in attributes
+            (self.transformed_names[attr], self.from_data(data, attr))
+            for attr in attributes if attr in data
         )
 
     def render_relationships(self, data, context):
@@ -132,6 +133,8 @@ def render_relationships(self, data, context):
                 raise IncludeInvalid('Invalid relationship to include: %s' % key)
 
         filtered = self.filter_by_fields(self.relationships, context.fields, lambda x: x[0])
+        # Filter by missing values in the data
+        filtered = (rel for rel in filtered if rel[0] in data)
         for (name, rel) in filtered:
             relationship, rel_included = self.render_relationship(data, name, rel, context)
             relationships[self.transformed_names[name]] = relationship
@@ -165,7 +168,7 @@ def filter_by_fields(self, names, fields, name_fn=lambda name: name):
         type_fields = fields[self.type]
         # This is essentially an intersection, but we preserve the order
         # of the attributes/relationships specified by the schema.
-        return [name for name in names if self.transformed_names[name_fn(name)] in type_fields]
+        return (name for name in names if self.transformed_names[name_fn(name)] in type_fields)
 
 
 class ResourceIdObject(BaseLinkedObject):
diff --git a/rest_framework_json_schema/tests/test_schema.py b/rest_framework_json_schema/tests/test_schema.py
index 33d1ac6..317fd88 100644
--- a/rest_framework_json_schema/tests/test_schema.py
+++ b/rest_framework_json_schema/tests/test_schema.py
@@ -227,6 +227,46 @@ class AlbumObject(ResourceObject):
         )))
         self.assertEqual(included, [])
 
+    def test_tolerate_missing_attributes(self):
+        """
+        To support write_only data, be tolerant if an attribute isn't in the data.
+        """
+        obj = ResourceObject(id='user_id', type='users', attributes=('first_name', 'last_name'))
+        primary, included = obj.render({
+            'user_id': '123',
+            'first_name': 'John'
+        }, Context(self.request))
+        self.assertEqual(primary, OrderedDict((
+            ('id', '123'),
+            ('type', 'users'),
+            ('attributes', OrderedDict((('first_name', 'John'),)))
+        )))
+        self.assertEqual(included, [])
+
+    def test_tolerate_missing_relationships(self):
+        """
+        To support write_only data, be tolerant if a relationship isn't in the data.
+        """
+        class AlbumObject(ResourceObject):
+            type = 'album'
+            relationships = ('artist', 'artist2')
+
+        # Empty to-one relationship: relationship is 'None'
+        # Empty to-many relationship: relationship is '[]'
+        # Single relationship: a ResourceIdObject
+        # To-Many: an array of ResourceIdObjects
+        obj = AlbumObject()
+
+        primary, included = obj.render({'id': '123', 'artist2': None}, Context(self.request))
+        self.assertEqual(primary, OrderedDict((
+            ('id', '123'),
+            ('type', 'album'),
+            ('relationships', OrderedDict((
+                ('artist2', OrderedDict((('data', None),))),
+            )))
+        )))
+        self.assertEqual(included, [])
+
     def test_render_included(self):
         """
         You can render included resources