diff --git a/rest_framework/relations.py b/rest_framework/relations.py
index 9bde79b19..af4dd1804 100644
--- a/rest_framework/relations.py
+++ b/rest_framework/relations.py
@@ -344,7 +344,7 @@ class HyperlinkedRelatedField(RelatedField):
             if data.startswith(prefix):
                 data = '/' + data[len(prefix):]
 
-        data = uri_to_iri(data)
+        data = uri_to_iri(parse.unquote(data))
 
         try:
             match = resolve(data)
diff --git a/tests/test_relations.py b/tests/test_relations.py
index c89293415..86ed623ae 100644
--- a/tests/test_relations.py
+++ b/tests/test_relations.py
@@ -153,6 +153,7 @@ class TestHyperlinkedRelatedField(APISimpleTestCase):
         self.queryset = MockQueryset([
             MockObject(pk=1, name='foobar'),
             MockObject(pk=2, name='bazABCqux'),
+            MockObject(pk=2, name='bazABC qux'),
         ])
         self.field = serializers.HyperlinkedRelatedField(
             view_name='example',
@@ -191,6 +192,10 @@ class TestHyperlinkedRelatedField(APISimpleTestCase):
         instance = self.field.to_internal_value('http://example.org/example/baz%41%42%43qux/')
         assert instance is self.queryset.items[1]
 
+    def test_hyperlinked_related_lookup_url_space_encoded_exists(self):
+        instance = self.field.to_internal_value('http://example.org/example/bazABC%20qux/')
+        assert instance is self.queryset.items[2]
+
     def test_hyperlinked_related_lookup_does_not_exist(self):
         with pytest.raises(serializers.ValidationError) as excinfo:
             self.field.to_internal_value('http://example.org/example/doesnotexist/')