diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index 74d0909587..c53d581858 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -142,7 +142,7 @@ def get_system_username():
         # if there is no corresponding entry in the /etc/passwd file
         # (a very restricted chroot environment, for example).
         return ''
-    if not six.PY3:
+    if six.PY2:
         try:
             result = result.decode(DEFAULT_LOCALE_ENCODING)
         except UnicodeDecodeError:
diff --git a/django/contrib/auth/tests/test_basic.py b/django/contrib/auth/tests/test_basic.py
index 6b1dd3af05..8dc9af5d85 100644
--- a/django/contrib/auth/tests/test_basic.py
+++ b/django/contrib/auth/tests/test_basic.py
@@ -16,7 +16,7 @@ from django.test.signals import setting_changed
 from django.test.utils import override_settings
 from django.utils import translation
 from django.utils.encoding import force_str
-from django.utils.six import binary_type, PY3, StringIO
+from django.utils.six import binary_type, PY2, StringIO
 
 
 @receiver(setting_changed)
@@ -39,7 +39,7 @@ def mock_inputs(inputs):
             class mock_getpass:
                 @staticmethod
                 def getpass(prompt=b'Password: ', stream=None):
-                    if not PY3:
+                    if PY2:
                         # getpass on Windows only supports prompt as bytestring (#19807)
                         assert isinstance(prompt, binary_type)
                     return inputs['password']
diff --git a/django/core/mail/message.py b/django/core/mail/message.py
index a24817ac90..2f24688d42 100644
--- a/django/core/mail/message.py
+++ b/django/core/mail/message.py
@@ -366,7 +366,7 @@ class EmailMessage(object):
             try:
                 filename.encode('ascii')
             except UnicodeEncodeError:
-                if not six.PY3:
+                if six.PY2:
                     filename = filename.encode('utf-8')
                 filename = ('utf-8', '', filename)
             attachment.add_header('Content-Disposition', 'attachment',
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 6483b97deb..92438ee91c 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -420,7 +420,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             'conv': django_conversions,
             'charset': 'utf8',
         }
-        if not six.PY3:
+        if six.PY2:
             kwargs['use_unicode'] = True
         settings_dict = self.settings_dict
         if settings_dict['USER']:
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index a6ff26dd36..1323a325c7 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -276,7 +276,7 @@ WHEN (new.%(col_name)s IS NULL)
         # http://cx-oracle.sourceforge.net/html/cursor.html#Cursor.statement
         # The DB API definition does not define this attribute.
         statement = cursor.statement
-        if statement and not six.PY3 and not isinstance(statement, unicode):
+        if statement and six.PY2 and not isinstance(statement, unicode):
             statement = statement.decode('utf-8')
         # Unlike Psycopg's `query` and MySQLdb`'s `_last_executed`, CxOracle's
         # `statement` doesn't contain the query parameters. refs #20010.
@@ -585,7 +585,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                 cursor.execute("SELECT 1 FROM DUAL WHERE DUMMY %s"
                                % self._standard_operators['contains'],
                                ['X'])
-            except DatabaseError: 
+            except DatabaseError:
                 self.operators = self._likec_operators
             else:
                 self.operators = self._standard_operators
@@ -627,7 +627,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                    and x.code == 2091 and 'ORA-02291' in x.message:
                     six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
                 raise
-    
+
     def schema_editor(self):
         "Returns a new instance of this backend's SchemaEditor"
         return DatabaseSchemaEditor(self)
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index c6cda55229..385733cb8d 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -84,7 +84,7 @@ Database.register_converter(str("decimal"), decoder(util.typecast_decimal))
 
 Database.register_adapter(datetime.datetime, adapt_datetime_with_timezone_support)
 Database.register_adapter(decimal.Decimal, util.rev_typecast_decimal)
-if not six.PY3:
+if six.PY2:
     Database.register_adapter(str, lambda s: s.decode('utf-8'))
     Database.register_adapter(SafeBytes, lambda s: s.decode('utf-8'))
 
diff --git a/django/db/models/base.py b/django/db/models/base.py
index 259d597636..2ca6f3ecc2 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -264,7 +264,7 @@ class ModelBase(type):
             return new_class
 
         new_class._prepare()
-        
+
         new_class._meta.app_cache.register_models(new_class._meta.app_label, new_class)
         # Because of the way imports happen (recursively), we may or may not be
         # the first time this model tries to register with the framework. There
@@ -449,7 +449,7 @@ class Model(six.with_metaclass(ModelBase)):
         return force_str('<%s: %s>' % (self.__class__.__name__, u))
 
     def __str__(self):
-        if not six.PY3 and hasattr(self, '__unicode__'):
+        if six.PY2 and hasattr(self, '__unicode__'):
             if type(self).__unicode__ == Model.__str__:
                 klass_name = type(self).__name__
                 raise RuntimeError("%s.__unicode__ is aliased to __str__. Did"
diff --git a/django/http/cookie.py b/django/http/cookie.py
index 62d5c61a4d..40cf58def8 100644
--- a/django/http/cookie.py
+++ b/django/http/cookie.py
@@ -49,7 +49,7 @@ else:
         if not _cookie_allows_colon_in_names:
             def load(self, rawdata):
                 self.bad_cookies = set()
-                if not six.PY3 and isinstance(rawdata, six.text_type):
+                if six.PY2 and isinstance(rawdata, six.text_type):
                     rawdata = force_str(rawdata)
                 super(SimpleCookie, self).load(rawdata)
                 for key in self.bad_cookies:
diff --git a/django/template/loaders/app_directories.py b/django/template/loaders/app_directories.py
index b25f14aace..44983065e4 100644
--- a/django/template/loaders/app_directories.py
+++ b/django/template/loaders/app_directories.py
@@ -15,7 +15,7 @@ from django.utils._os import safe_join
 from django.utils import six
 
 # At compile time, cache the directories to search.
-if not six.PY3:
+if six.PY2:
     fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
 app_template_dirs = []
 for app in settings.INSTALLED_APPS:
@@ -25,7 +25,7 @@ for app in settings.INSTALLED_APPS:
         raise ImproperlyConfigured('ImportError %s: %s' % (app, e.args[0]))
     template_dir = os.path.join(os.path.dirname(mod.__file__), 'templates')
     if os.path.isdir(template_dir):
-        if not six.PY3:
+        if six.PY2:
             template_dir = template_dir.decode(fs_encoding)
         app_template_dirs.append(template_dir)
 
diff --git a/django/template/loaders/eggs.py b/django/template/loaders/eggs.py
index b7dcc75be3..7da180323a 100644
--- a/django/template/loaders/eggs.py
+++ b/django/template/loaders/eggs.py
@@ -27,7 +27,7 @@ class Loader(BaseLoader):
                     resource = resource_string(app, pkg_name)
                 except Exception:
                     continue
-                if not six.PY3:
+                if six.PY2:
                     resource = resource.decode(settings.FILE_CHARSET)
                 return (resource, 'egg:%s:%s' % (app, pkg_name))
         raise TemplateDoesNotExist(template_name)
diff --git a/django/utils/_os.py b/django/utils/_os.py
index 607e02c94d..3e60c1082c 100644
--- a/django/utils/_os.py
+++ b/django/utils/_os.py
@@ -12,7 +12,7 @@ except NameError:
     class WindowsError(Exception):
         pass
 
-if not six.PY3:
+if six.PY2:
     fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
 
 
@@ -38,7 +38,7 @@ def upath(path):
     """
     Always return a unicode path.
     """
-    if not six.PY3 and not isinstance(path, six.text_type):
+    if six.PY2 and not isinstance(path, six.text_type):
         return path.decode(fs_encoding)
     return path
 
@@ -47,7 +47,7 @@ def npath(path):
     Always return a native path, that is unicode on Python 3 and bytestring on
     Python 2.
     """
-    if not six.PY3 and not isinstance(path, bytes):
+    if six.PY2 and not isinstance(path, bytes):
         return path.encode(fs_encoding)
     return path
 
diff --git a/django/utils/encoding.py b/django/utils/encoding.py
index aa0218ca6b..bb7c38fea8 100644
--- a/django/utils/encoding.py
+++ b/django/utils/encoding.py
@@ -30,7 +30,7 @@ def python_2_unicode_compatible(klass):
     To support Python 2 and 3 with a single code base, define a __str__ method
     returning text and apply this decorator to the class.
     """
-    if not six.PY3:
+    if six.PY2:
         klass.__unicode__ = klass.__str__
         klass.__str__ = lambda self: self.__unicode__().encode('utf-8')
     return klass
diff --git a/django/utils/feedgenerator.py b/django/utils/feedgenerator.py
index de32b9f8cc..3aa6b2cb23 100644
--- a/django/utils/feedgenerator.py
+++ b/django/utils/feedgenerator.py
@@ -46,7 +46,7 @@ def rfc2822_date(date):
     dow = days[date.weekday()]
     month = months[date.month - 1]
     time_str = date.strftime('%s, %%d %s %%Y %%H:%%M:%%S ' % (dow, month))
-    if not six.PY3:             # strftime returns a byte string in Python 2
+    if six.PY2:             # strftime returns a byte string in Python 2
         time_str = time_str.decode('utf-8')
     if is_aware(date):
         offset = date.tzinfo.utcoffset(date)
@@ -60,7 +60,7 @@ def rfc3339_date(date):
     # Support datetime objects older than 1900
     date = datetime_safe.new_datetime(date)
     time_str = date.strftime('%Y-%m-%dT%H:%M:%S')
-    if not six.PY3:             # strftime returns a byte string in Python 2
+    if six.PY2:             # strftime returns a byte string in Python 2
         time_str = time_str.decode('utf-8')
     if is_aware(date):
         offset = date.tzinfo.utcoffset(date)
diff --git a/django/utils/functional.py b/django/utils/functional.py
index 9cc703fe84..bfd59e5340 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -167,7 +167,7 @@ def lazy(func, *resultclasses):
             return hash(self.__cast())
 
         def __mod__(self, rhs):
-            if self._delegate_bytes and not six.PY3:
+            if self._delegate_bytes and six.PY2:
                 return bytes(self) % rhs
             elif self._delegate_text:
                 return six.text_type(self) % rhs
diff --git a/django/utils/http.py b/django/utils/http.py
index 9b36ab91d7..a751dea3c6 100644
--- a/django/utils/http.py
+++ b/django/utils/http.py
@@ -170,7 +170,7 @@ def base36_to_int(s):
     value = int(s, 36)
     # ... then do a final check that the value will fit into an int to avoid
     # returning a long (#15067). The long type was removed in Python 3.
-    if not six.PY3 and value > sys.maxint:
+    if six.PY2 and value > sys.maxint:
         raise ValueError("Base36 input too large")
     return value
 
@@ -182,7 +182,7 @@ def int_to_base36(i):
     factor = 0
     if i < 0:
         raise ValueError("Negative base36 conversion input.")
-    if not six.PY3:
+    if six.PY2:
         if not isinstance(i, six.integer_types):
             raise TypeError("Non-integer base36 conversion input.")
         if i > sys.maxint:
diff --git a/django/utils/text.py b/django/utils/text.py
index e89f7df0c6..eeff5c5a2e 100644
--- a/django/utils/text.py
+++ b/django/utils/text.py
@@ -12,7 +12,7 @@ from django.utils.six.moves import html_entities
 from django.utils.translation import ugettext_lazy, ugettext as _, pgettext
 from django.utils.safestring import mark_safe
 
-if not six.PY3:
+if six.PY2:
     # Import force_unicode even though this module doesn't use it, because some
     # people rely on it being here.
     from django.utils.encoding import force_unicode
diff --git a/docs/topics/python3.txt b/docs/topics/python3.txt
index 9a0438e9e5..8f2306962b 100644
--- a/docs/topics/python3.txt
+++ b/docs/topics/python3.txt
@@ -376,15 +376,13 @@ explicitly tries both locations, as follows::
     except ImportError:     # Python 2
         from urlparse import urlparse, urlunparse
 
-PY3
+PY2
 ~~~
 
-If you need different code in Python 2 and Python 3, check :data:`six.PY3`::
+If you need different code in Python 2 and Python 3, check :data:`six.PY2`::
 
-    if six.PY3:
-        # do stuff Python 3-wise
-    else:
-        # do stuff Python 2-wise
+    if six.PY2:
+        # compatibility code for Python 2
 
 This is a last resort solution when :mod:`six` doesn't provide an appropriate
 function.
diff --git a/tests/base/models.py b/tests/base/models.py
index d47ddcfd66..98d379337c 100644
--- a/tests/base/models.py
+++ b/tests/base/models.py
@@ -19,7 +19,7 @@ class MyModel(six.with_metaclass(CustomBaseModel, models.Model)):
 # This is done to ensure that for Python2 only, defining metaclasses
 # still does not fail to create the model.
 
-if not six.PY3:
+if six.PY2:
     class MyModel(models.Model):
         """Model subclass with a custom base using __metaclass__."""
         __metaclass__ = CustomBaseModel
diff --git a/tests/basic/tests.py b/tests/basic/tests.py
index 2204989823..fb3b06a543 100644
--- a/tests/basic/tests.py
+++ b/tests/basic/tests.py
@@ -373,7 +373,7 @@ class ModelTest(TestCase):
              "<Article: Third article>"])
 
         # Slicing works with longs (Python 2 only -- Python 3 doesn't have longs).
-        if not six.PY3:
+        if six.PY2:
             self.assertEqual(Article.objects.all()[long(0)], a)
             self.assertQuerysetEqual(Article.objects.all()[long(1):long(3)],
                 ["<Article: Second article>", "<Article: Third article>"])
diff --git a/tests/defaultfilters/tests.py b/tests/defaultfilters/tests.py
index 7db872001d..86bdbf9992 100644
--- a/tests/defaultfilters/tests.py
+++ b/tests/defaultfilters/tests.py
@@ -89,7 +89,7 @@ class DefaultFiltersTests(TestCase):
     # The test above fails because of Python 2's float handling. Floats with
     # many zeroes after the decimal point should be passed in as another type
     # such as unicode or Decimal.
-    if not six.PY3:
+    if six.PY2:
         test_floatformat_py2_fail = unittest.expectedFailure(test_floatformat_py2_fail)
 
 
diff --git a/tests/httpwrappers/tests.py b/tests/httpwrappers/tests.py
index 4ee342c252..356818d2ef 100644
--- a/tests/httpwrappers/tests.py
+++ b/tests/httpwrappers/tests.py
@@ -46,7 +46,7 @@ class QueryDictTests(unittest.TestCase):
     def test_immutable_basic_operations(self):
         q = QueryDict(str(''))
         self.assertEqual(q.getlist('foo'), [])
-        if not six.PY3:
+        if six.PY2:
             self.assertEqual(q.has_key('foo'), False)
         self.assertEqual('foo' in q, False)
         self.assertEqual(list(six.iteritems(q)), [])
@@ -72,10 +72,10 @@ class QueryDictTests(unittest.TestCase):
         self.assertRaises(AttributeError, q.setlist, 'foo', ['bar'])
         self.assertRaises(AttributeError, q.appendlist, 'foo', ['bar'])
 
-        if not six.PY3:
+        if six.PY2:
             self.assertTrue(q.has_key('foo'))
         self.assertTrue('foo' in q)
-        if not six.PY3:
+        if six.PY2:
             self.assertFalse(q.has_key('bar'))
         self.assertFalse('bar' in q)
 
@@ -131,7 +131,7 @@ class QueryDictTests(unittest.TestCase):
         q.appendlist('foo', 'another')
         self.assertEqual(q.getlist('foo'), ['bar', 'baz', 'another'])
         self.assertEqual(q['foo'], 'another')
-        if not six.PY3:
+        if six.PY2:
             self.assertTrue(q.has_key('foo'))
         self.assertTrue('foo' in q)
 
@@ -176,10 +176,10 @@ class QueryDictTests(unittest.TestCase):
         self.assertRaises(AttributeError, q.setlist, 'foo', ['bar', 'baz'])
         self.assertRaises(AttributeError, q.appendlist, 'foo', ['bar'])
 
-        if not six.PY3:
+        if six.PY2:
             self.assertEqual(q.has_key('vote'), True)
         self.assertEqual('vote' in q, True)
-        if not six.PY3:
+        if six.PY2:
             self.assertEqual(q.has_key('foo'), False)
         self.assertEqual('foo' in q, False)
         self.assertEqual(list(six.iteritems(q)), [('vote', 'no')])
@@ -195,7 +195,7 @@ class QueryDictTests(unittest.TestCase):
         self.assertRaises(AttributeError, q.setdefault, 'foo', 'bar')
         self.assertRaises(AttributeError, q.__delitem__, 'vote')
 
-    if not six.PY3:
+    if six.PY2:
         def test_invalid_input_encoding(self):
             """
             QueryDicts must be able to handle invalid input encoding (in this
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index 12e325b773..cd167616e7 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -89,7 +89,7 @@ class TranslationTests(TransRealMixin, TestCase):
         s4 = ugettext_lazy('Some other string')
         self.assertEqual(False, s == s4)
 
-        if not six.PY3:
+        if six.PY2:
             # On Python 2, gettext_lazy should not transform a bytestring to unicode
             self.assertEqual(gettext_lazy(b"test").upper(), b"TEST")
 
diff --git a/tests/signing/tests.py b/tests/signing/tests.py
index 05c8b3dc74..5c5c2b1da7 100644
--- a/tests/signing/tests.py
+++ b/tests/signing/tests.py
@@ -48,7 +48,7 @@ class TestSigner(TestCase):
             'jkw osanteuh ,rcuh nthu aou oauh ,ud du',
             '\u2019',
         ]
-        if not six.PY3:
+        if six.PY2:
             examples.append(b'a byte string')
         for example in examples:
             signed = signer.sign(example)
@@ -79,7 +79,7 @@ class TestSigner(TestCase):
             'a unicode string \u2019',
             {'a': 'dictionary'},
         ]
-        if not six.PY3:
+        if six.PY2:
             objects.append(b'a byte string')
         for o in objects:
             self.assertNotEqual(o, signing.dumps(o))
diff --git a/tests/test_utils/doctest_output.py b/tests/test_utils/doctest_output.py
index 724364428a..0d1e94d037 100644
--- a/tests/test_utils/doctest_output.py
+++ b/tests/test_utils/doctest_output.py
@@ -59,7 +59,7 @@ __test__ = {"API_TEST": r"""
 
 """}
 
-if not six.PY3:
+if six.PY2:
     __test__["API_TEST"] += """
 >>> def produce_long():
 ...     return 42L
diff --git a/tests/utils_tests/test_datastructures.py b/tests/utils_tests/test_datastructures.py
index 5563a0fc4f..7984837053 100644
--- a/tests/utils_tests/test_datastructures.py
+++ b/tests/utils_tests/test_datastructures.py
@@ -49,7 +49,7 @@ class SortedDictTests(SimpleTestCase):
         self.d2[7] = 'lucky number 7'
         self.assertEqual(list(six.iterkeys(self.d2)), [1, 9, 0, 7])
 
-    if not six.PY3:
+    if six.PY2:
         def test_change_keys(self):
             """
             Changing the keys won't do anything, it's only a copy of the
diff --git a/tests/utils_tests/test_http.py b/tests/utils_tests/test_http.py
index 581eb1dcd7..f68ac33503 100644
--- a/tests/utils_tests/test_http.py
+++ b/tests/utils_tests/test_http.py
@@ -115,12 +115,12 @@ class TestUtilsHttp(unittest.TestCase):
         # reciprocity works
         for n in [0, 1, 1000, 1000000]:
             self.assertEqual(n, http.base36_to_int(http.int_to_base36(n)))
-        if not six.PY3:
+        if six.PY2:
             self.assertEqual(sys.maxint, http.base36_to_int(http.int_to_base36(sys.maxint)))
 
         # bad input
         self.assertRaises(ValueError, http.int_to_base36, -1)
-        if not six.PY3:
+        if six.PY2:
             self.assertRaises(ValueError, http.int_to_base36, sys.maxint + 1)
         for n in ['1', 'foo', {1: 2}, (1, 2, 3), 3.141]:
             self.assertRaises(TypeError, http.int_to_base36, n)
diff --git a/tests/utils_tests/test_simplelazyobject.py b/tests/utils_tests/test_simplelazyobject.py
index f16b5e4da1..8dd427e86a 100644
--- a/tests/utils_tests/test_simplelazyobject.py
+++ b/tests/utils_tests/test_simplelazyobject.py
@@ -181,7 +181,7 @@ class TestUtilsSimpleLazyObject(TestCase):
         pickled = pickle.dumps(x, 1)
         pickled = pickle.dumps(x, 2)
 
-        if not six.PY3:
+        if six.PY2:
             import cPickle
 
             # This would fail with "TypeError: expected string or Unicode object, NoneType found".