diff --git a/django/newforms/widgets.py b/django/newforms/widgets.py
index 16e617301b..02cecca9aa 100644
--- a/django/newforms/widgets.py
+++ b/django/newforms/widgets.py
@@ -401,6 +401,18 @@ class SelectMultiple(Widget):
         if isinstance(data, MultiValueDict):
             return data.getlist(name)
         return data.get(name, None)
+    
+    def _has_changed(self, initial, data):
+        if initial is None:
+            initial = []
+        if data is None:
+            data = []
+        if len(initial) != len(data):
+            return True
+        for value1, value2 in zip(initial, data):
+            if force_unicode(value1) != force_unicode(value2):
+                return True
+        return False
 
 class RadioInput(StrAndUnicode):
     """
diff --git a/tests/regressiontests/forms/widgets.py b/tests/regressiontests/forms/widgets.py
index 4944a26b74..e20ea15175 100644
--- a/tests/regressiontests/forms/widgets.py
+++ b/tests/regressiontests/forms/widgets.py
@@ -612,6 +612,20 @@ If 'choices' is passed to both the constructor and render(), then they'll both b
 >>> w.render('nums', ['ŠĐĆŽćžšđ'], choices=[('ŠĐĆŽćžšđ', 'ŠĐabcĆŽćžšđ'), ('ćžšđ', 'abcćžšđ')])
 u'<select multiple="multiple" name="nums">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="\u0160\u0110\u0106\u017d\u0107\u017e\u0161\u0111" selected="selected">\u0160\u0110abc\u0106\u017d\u0107\u017e\u0161\u0111</option>\n<option value="\u0107\u017e\u0161\u0111">abc\u0107\u017e\u0161\u0111</option>\n</select>'
 
+# Test the usage of _has_changed
+>>> w._has_changed(None, None)
+False
+>>> w._has_changed([], None)
+False
+>>> w._has_changed(None, [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'2'])
+False
+>>> w._has_changed([1, 2], [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'3'])
+True
+
 # RadioSelect Widget ##########################################################
 
 >>> w = RadioSelect()
@@ -910,6 +924,20 @@ If 'choices' is passed to both the constructor and render(), then they'll both b
 <li><label><input type="checkbox" name="escape" value="good" /> you &gt; me</label></li>
 </ul>
 
+# Test the usage of _has_changed
+>>> w._has_changed(None, None)
+False
+>>> w._has_changed([], None)
+False
+>>> w._has_changed(None, [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'2'])
+False
+>>> w._has_changed([1, 2], [u'1'])
+True
+>>> w._has_changed([1, 2], [u'1', u'3'])
+True
+
 # Unicode choices are correctly rendered as HTML
 >>> w.render('nums', ['ŠĐĆŽćžšđ'], choices=[('ŠĐĆŽćžšđ', 'ŠĐabcĆŽćžšđ'), ('ćžšđ', 'abcćžšđ')])
 u'<ul>\n<li><label><input type="checkbox" name="nums" value="1" /> 1</label></li>\n<li><label><input type="checkbox" name="nums" value="2" /> 2</label></li>\n<li><label><input type="checkbox" name="nums" value="3" /> 3</label></li>\n<li><label><input checked="checked" type="checkbox" name="nums" value="\u0160\u0110\u0106\u017d\u0107\u017e\u0161\u0111" /> \u0160\u0110abc\u0106\u017d\u0107\u017e\u0161\u0111</label></li>\n<li><label><input type="checkbox" name="nums" value="\u0107\u017e\u0161\u0111" /> abc\u0107\u017e\u0161\u0111</label></li>\n</ul>'