diff --git a/Doc/distutils/setupscript.rst b/Doc/distutils/setupscript.rst
--- a/Doc/distutils/setupscript.rst
+++ b/Doc/distutils/setupscript.rst
@@ -602,19 +602,19 @@ Notes:
 (2)
     It is recommended that versions take the form *major.minor[.patch[.sub]]*.
 
 (3)
     Either the author or the maintainer must be identified. If maintainer is
     provided, distutils lists it as the author in :file:`PKG-INFO`.
 
 (4)
-    These fields should not be used if your package is to be compatible with Python
-    versions prior to 2.2.3 or 2.3.  The list is available from the `PyPI website
-    <http://pypi.python.org/pypi>`_.
+    This field must be a list. Otherwise, a :exc:`TypeError` is raised. The
+    valid classifiers are listed on `PyPI
+    <http://pypi.python.org/pypi?:action=list_classifiers>`_.
 
 (5)
     The ``long_description`` field is used by PyPI when you are
     :ref:`registering <package-register>` a package, to
     :ref:`build its home page <package-display>`.
 
 (6)
     The ``license`` field is a text indicating the license covering the
@@ -645,17 +645,17 @@ information is sometimes used to indicat
 (for final pre-release release testing). Some examples:
 
 0.1.0
     the first, experimental release of a package
 
 1.0.1a2
     the second alpha release of the first patch version of 1.0
 
-:option:`classifiers` are specified in a Python list::
+:option:`classifiers` are must be specified in a Python list::
 
     setup(...,
           classifiers=[
               'Development Status :: 4 - Beta',
               'Environment :: Console',
               'Environment :: Web Environment',
               'Intended Audience :: End Users/Desktop',
               'Intended Audience :: Developers',
@@ -666,28 +666,19 @@ 1.0.1a2
               'Operating System :: POSIX',
               'Programming Language :: Python',
               'Topic :: Communications :: Email',
               'Topic :: Office/Business',
               'Topic :: Software Development :: Bug Tracking',
               ],
           )
 
-If you wish to include classifiers in your :file:`setup.py` file and also wish
-to remain backwards-compatible with Python releases prior to 2.2.3, then you can
-include the following code fragment in your :file:`setup.py` before the
-:func:`setup` call. ::
-
-    # patch distutils if it can't cope with the "classifiers" or
-    # "download_url" keywords
-    from sys import version
-    if version < '2.2.3':
-        from distutils.dist import DistributionMetadata
-        DistributionMetadata.classifiers = None
-        DistributionMetadata.download_url = None
+.. versionchanged:: 3.5
+   :class:`~distutils.dist.Distribution` now raises :exc:`TypeError` if
+   :option:`classifiers` are not specified in a Python list.
 
 
 .. _debug-setup-script:
 
 Debugging the setup script
 ==========================
 
 Sometimes things go wrong, and the setup script doesn't do what the developer
diff --git a/Lib/distutils/dist.py b/Lib/distutils/dist.py
--- a/Lib/distutils/dist.py
+++ b/Lib/distutils/dist.py
@@ -1191,16 +1191,22 @@ class DistributionMetadata:
         return self.keywords or []
 
     def get_platforms(self):
         return self.platforms or ["UNKNOWN"]
 
     def get_classifiers(self):
         return self.classifiers or []
 
+    def set_classifiers(self, value):
+        if not isinstance(value, list):
+            msg = "classifiers should be a 'list', not '%s'"
+            raise TypeError(msg % type(value).__name__)
+        self.classifiers = value
+
     def get_download_url(self):
         return self.download_url or "UNKNOWN"
 
     # PEP 314
     def get_requires(self):
         return self.requires or []
 
     def set_requires(self, value):
diff --git a/Lib/distutils/tests/test_dist.py b/Lib/distutils/tests/test_dist.py
--- a/Lib/distutils/tests/test_dist.py
+++ b/Lib/distutils/tests/test_dist.py
@@ -335,16 +335,32 @@ class MetadataTestCase(support.TempdirMa
 
     def test_classifier(self):
         attrs = {'name': 'Boa', 'version': '3.0',
                  'classifiers': ['Programming Language :: Python :: 3']}
         dist = Distribution(attrs)
         meta = self.format_metadata(dist)
         self.assertIn('Metadata-Version: 1.1', meta)
 
+    def test_classifier_list(self):
+        attrs = {'name': 'Boa', 'version': '3.0',
+                 'classifiers': ['Programming Language :: Python :: 3']}
+        dist = Distribution(attrs)
+        self.assertListEqual(dist.get_classifiers(),
+                             ['Programming Language :: Python :: 3'])
+
+    def test_classifier_tuple(self):
+        attrs = {'name': 'Boa', 'version': '3.0',
+                 'classifiers': ('Programming Language :: Python :: 3',)}
+        with self.assertRaises(TypeError) as cm:
+            dist = Distribution(attrs)
+            dist.get_classifiers()
+        self.assertEqual(str(cm.exception),
+                         "classifiers should be a 'list', not 'tuple'")
+
     def test_download_url(self):
         attrs = {'name': 'Boa', 'version': '3.0',
                  'download_url': 'http://example.org/boa'}
         dist = Distribution(attrs)
         meta = self.format_metadata(dist)
         self.assertIn('Metadata-Version: 1.1', meta)
 
     def test_long_description(self):