diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index 7afddfd82..80b7c6d6d 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -367,7 +367,7 @@ class Serializer(BaseSerializer):
         # We override the default field access in order to support
         # nested HTML forms.
         if html.is_html_input(dictionary):
-            return html.parse_html_dict(dictionary, prefix=self.field_name)
+            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
         return dictionary.get(self.field_name, empty)
 
     def run_validation(self, data=empty):
diff --git a/tests/test_serializer_nested.py b/tests/test_serializer_nested.py
index f5e4b26ad..b14a58c9e 100644
--- a/tests/test_serializer_nested.py
+++ b/tests/test_serializer_nested.py
@@ -1,3 +1,5 @@
+from django.http import QueryDict
+
 from rest_framework import serializers
 
 
@@ -38,3 +40,32 @@ class TestNestedSerializer:
         }
         serializer = self.Serializer()
         assert serializer.data == expected_data
+
+
+class TestNotRequiredNestedSerializer:
+    def setup(self):
+        class NestedSerializer(serializers.Serializer):
+            one = serializers.IntegerField(max_value=10)
+
+        class TestSerializer(serializers.Serializer):
+            nested = NestedSerializer(required=False)
+
+        self.Serializer = TestSerializer
+
+    def test_json_validate(self):
+        input_data = {}
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+
+        input_data = {'nested': {'one': '1'}}
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+
+    def test_multipart_validate(self):
+        input_data = QueryDict('')
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()
+
+        input_data = QueryDict('nested[one]=1')
+        serializer = self.Serializer(data=input_data)
+        assert serializer.is_valid()