diff --git a/django/template/defaulttags.py b/django/template/defaulttags.py
index 4b0a4d1fa6..03a6245de8 100644
--- a/django/template/defaulttags.py
+++ b/django/template/defaulttags.py
@@ -806,8 +806,8 @@ def do_if(parser, token):
     Arguments and operators _must_ have a space between them, so
     ``{% if 1>2 %}`` is not a valid if tag.
 
-    All supported operators are: ``or``, ``and``, ``in``, ``==`` (or ``=``),
-    ``!=``, ``>``, ``>=``, ``<`` and ``<=``.
+    All supported operators are: ``or``, ``and``, ``in``, ``not in``
+    ``==`` (or ``=``), ``!=``, ``>``, ``>=``, ``<`` and ``<=``.
 
     Operator precedence follows Python.
     """
diff --git a/django/template/smartif.py b/django/template/smartif.py
index e8a08e9087..c4e3a06b7c 100644
--- a/django/template/smartif.py
+++ b/django/template/smartif.py
@@ -97,6 +97,7 @@ OPERATORS = {
     'and': infix(7, lambda x, y: x and y),
     'not': prefix(8, operator.not_),
     'in': infix(9, lambda x, y: x in y),
+    'not in': infix(9, lambda x, y: x not in y),
     '=': infix(10, operator.eq),
     '==': infix(10, operator.eq),
     '!=': infix(10, operator.ne),
@@ -150,11 +151,23 @@ class IfParser(object):
     error_class = ValueError
 
     def __init__(self, tokens):
-        self.tokens = map(self.translate_tokens, tokens)
+        # pre-pass necessary to turn  'not','in' into single token 
+        l = len(tokens)
+        mapped_tokens = []
+        i = 0
+        while i < l:
+            token = tokens[i]
+            if token == "not" and i + 1 < l and tokens[i+1] == "in":
+                token = "not in"
+                i += 1 # skip 'in'
+            mapped_tokens.append(self.translate_token(token))
+            i += 1
+
+        self.tokens = mapped_tokens
         self.pos = 0
         self.current_token = self.next()
 
-    def translate_tokens(self, token):
+    def translate_token(self, token):
         try:
             op = OPERATORS[token]
         except (KeyError, TypeError):
diff --git a/docs/ref/templates/builtins.txt b/docs/ref/templates/builtins.txt
index 8bc4f8e4f6..c613c58107 100644
--- a/docs/ref/templates/builtins.txt
+++ b/docs/ref/templates/builtins.txt
@@ -440,6 +440,11 @@ how ``x in y`` will be interpreted::
       instance that belongs to the QuerySet.
     {% endif %}
 
+``not in`` operator
+~~~~~~~~~~~~~~~~~~~~
+
+Not contained within.  This is the negation of the ``in`` operator.
+
 
 The comparison operators cannot be 'chained' like in Python or in mathematical
 notation. For example, instead of using::
diff --git a/docs/releases/1.2.txt b/docs/releases/1.2.txt
index f30e84a77d..24dc483f73 100644
--- a/docs/releases/1.2.txt
+++ b/docs/releases/1.2.txt
@@ -636,9 +636,9 @@ You can now do this:
 There's really no reason to use ``{% ifequal %}`` or ``{% ifnotequal %}``
 anymore, unless you're the nostalgic type.
 
-The operators supported are ``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=`` and
-``in``, all of which work like the Python operators, in addition to ``and``,
-``or`` and ``not``, which were already supported.
+The operators supported are ``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=``,
+``in`` and ``not in``, all of which work like the Python operators, in addition
+ to ``and``, ``or`` and ``not``, which were already supported.
 
 Also, filters may now be used in the ``if`` expression. For example:
 
diff --git a/tests/regressiontests/templates/smartif.py b/tests/regressiontests/templates/smartif.py
index 0114753830..5e5d7704e7 100644
--- a/tests/regressiontests/templates/smartif.py
+++ b/tests/regressiontests/templates/smartif.py
@@ -27,6 +27,13 @@ class SmartIfTests(unittest.TestCase):
         self.assertCalcEqual(False, [1, 'in', None])
         self.assertCalcEqual(False, [None, 'in', list_])
 
+    def test_not_in(self):
+        list_ = [1,2,3]
+        self.assertCalcEqual(False, [1, 'not', 'in', list_])
+        self.assertCalcEqual(True, [4, 'not', 'in', list_])
+        self.assertCalcEqual(False, [1, 'not', 'in', None])
+        self.assertCalcEqual(True, [None, 'not', 'in', list_])
+
     def test_precedence(self):
         # (False and False) or True == True   <- we want this one, like Python
         # False and (False or True) == False
diff --git a/tests/regressiontests/templates/tests.py b/tests/regressiontests/templates/tests.py
index 1af3637158..e603ec33c2 100644
--- a/tests/regressiontests/templates/tests.py
+++ b/tests/regressiontests/templates/tests.py
@@ -611,6 +611,12 @@ class Templates(unittest.TestCase):
             'if-tag-lte-01': ("{% if 1 <= 1 %}yes{% else %}no{% endif %}", {}, "yes"),
             'if-tag-lte-02': ("{% if 2 <= 1 %}yes{% else %}no{% endif %}", {}, "no"),
 
+            # Contains
+            'if-tag-in-01': ("{% if 1 in x %}yes{% else %}no{% endif %}", {'x':[1]}, "yes"),
+            'if-tag-in-02': ("{% if 2 in x %}yes{% else %}no{% endif %}", {'x':[1]}, "no"),
+            'if-tag-not-in-01': ("{% if 1 not in x %}yes{% else %}no{% endif %}", {'x':[1]}, "no"),
+            'if-tag-not-in-02': ("{% if 2 not in x %}yes{% else %}no{% endif %}", {'x':[1]}, "yes"),
+
             # AND
             'if-tag-and01': ("{% if foo and bar %}yes{% else %}no{% endif %}", {'foo': True, 'bar': True}, 'yes'),
             'if-tag-and02': ("{% if foo and bar %}yes{% else %}no{% endif %}", {'foo': True, 'bar': False}, 'no'),