diff --git a/django/utils/httpwrappers.py b/django/utils/httpwrappers.py
index 32f2bfb8f7..6a64592eaa 100644
--- a/django/utils/httpwrappers.py
+++ b/django/utils/httpwrappers.py
@@ -69,7 +69,7 @@ class QueryDict(MultiValueDict):
     def __init__(self, query_string):
         MultiValueDict.__init__(self)
         self._mutable = True
-        for key, value in parse_qsl(query_string, True): # keep_blank_values=True
+        for key, value in parse_qsl((query_string or ''), True): # keep_blank_values=True
             self.appendlist(key, value)
         self._mutable = False