diff --git a/django/core/serializers/json.py b/django/core/serializers/json.py
index 3bac24d33a..4ba0d7fd79 100644
--- a/django/core/serializers/json.py
+++ b/django/core/serializers/json.py
@@ -61,13 +61,12 @@ def Deserializer(stream_or_string, **options):
     """
     Deserialize a stream or string of JSON data.
     """
+    if not isinstance(stream_or_string, (bytes, six.string_types)):
+        stream_or_string = stream_or_string.read()
     if isinstance(stream_or_string, bytes):
         stream_or_string = stream_or_string.decode('utf-8')
     try:
-        if isinstance(stream_or_string, six.string_types):
-            objects = json.loads(stream_or_string)
-        else:
-            objects = json.load(stream_or_string)
+        objects = json.loads(stream_or_string)
         for obj in PythonDeserializer(objects, **options):
             yield obj
     except GeneratorExit: