diff --git a/django/utils/datastructures.py b/django/utils/datastructures.py
index f46b57c151..a2b78a31c5 100644
--- a/django/utils/datastructures.py
+++ b/django/utils/datastructures.py
@@ -145,7 +145,7 @@ class SortedDict(dict):
         """Returns a copy of this object."""
         # This way of initializing the copy means it works for subclasses, too.
         obj = self.__class__(self)
-        obj.keyOrder = self.keyOrder
+        obj.keyOrder = self.keyOrder[:]
         return obj
 
     def __repr__(self):
diff --git a/tests/regressiontests/datastructures/tests.py b/tests/regressiontests/datastructures/tests.py
index b5dc5d171b..172057f080 100644
--- a/tests/regressiontests/datastructures/tests.py
+++ b/tests/regressiontests/datastructures/tests.py
@@ -77,6 +77,8 @@ MultiValueDictKeyError: "Key 'lastname' not found in <MultiValueDict: {'position
 'not one'
 >>> d.keys() == d.copy().keys()
 True
+>>> d2 = d.copy()
+>>> d2['four'] = 'four'
 >>> print repr(d)
 {'one': 'not one', 'two': 'two', 'three': 'three'}
 >>> d.pop('one', 'missing')