diff --git a/tests/admin_filters/tests.py b/tests/admin_filters/tests.py
index ce659f937fe..6db2147e51b 100644
--- a/tests/admin_filters/tests.py
+++ b/tests/admin_filters/tests.py
@@ -460,7 +460,7 @@ class ListFiltersTests(TestCase):
         self.assertEqual(choice['query_string'], '?date_registered__isnull=False')
 
     @unittest.skipIf(
-        sys.platform.startswith('win'),
+        sys.platform == 'win32',
         "Windows doesn't support setting a timezone that differs from the "
         "system timezone."
     )
diff --git a/tests/asgi/tests.py b/tests/asgi/tests.py
index eee12b95ba0..3a26d3130f8 100644
--- a/tests/asgi/tests.py
+++ b/tests/asgi/tests.py
@@ -78,7 +78,7 @@ class ASGITest(SimpleTestCase):
             set(response_start['headers']),
             {
                 (b'Content-Length', str(len(test_file_contents)).encode('ascii')),
-                (b'Content-Type', b'text/plain' if sys.platform.startswith('win') else b'text/x-python'),
+                (b'Content-Type', b'text/plain' if sys.platform == 'win32' else b'text/x-python'),
                 (b'Content-Disposition', b'inline; filename="urls.py"'),
             },
         )
diff --git a/tests/file_storage/tests.py b/tests/file_storage/tests.py
index be6e11de93c..9b41f5250db 100644
--- a/tests/file_storage/tests.py
+++ b/tests/file_storage/tests.py
@@ -771,7 +771,7 @@ class FileFieldStorageTests(TestCase):
                 o.delete()
 
     @unittest.skipIf(
-        sys.platform.startswith('win'),
+        sys.platform == 'win32',
         "Windows supports at most 260 characters in a path.",
     )
     def test_extended_length_storage(self):
@@ -897,7 +897,7 @@ class FileSaveRaceConditionTest(SimpleTestCase):
         self.assertRegex(files[1], 'conflict_%s' % FILE_SUFFIX_REGEX)
 
 
-@unittest.skipIf(sys.platform.startswith('win'), "Windows only partially supports umasks and chmod.")
+@unittest.skipIf(sys.platform == 'win32', "Windows only partially supports umasks and chmod.")
 class FileStoragePermissions(unittest.TestCase):
     def setUp(self):
         self.umask = 0o027
diff --git a/tests/fixtures/tests.py b/tests/fixtures/tests.py
index 7390ab54f9a..02dd38e6350 100644
--- a/tests/fixtures/tests.py
+++ b/tests/fixtures/tests.py
@@ -376,7 +376,7 @@ class FixtureLoadingTests(DumpDataAssertMixin, TestCase):
         with self.assertRaisesMessage(management.CommandError, "Unknown model: fixtures.FooModel"):
             self._dumpdata_assert(['fixtures', 'sites'], '', exclude_list=['fixtures.FooModel'])
 
-    @unittest.skipIf(sys.platform.startswith('win'), "Windows doesn't support '?' in filenames.")
+    @unittest.skipIf(sys.platform == 'win32', "Windows doesn't support '?' in filenames.")
     def test_load_fixture_with_special_characters(self):
         management.call_command('loaddata', 'fixture_with[special]chars', verbosity=0)
         self.assertQuerysetEqual(Article.objects.all(), ['<Article: How To Deal With Special Characters>'])
diff --git a/tests/model_fields/test_filefield.py b/tests/model_fields/test_filefield.py
index 9330a2eba25..9642e7e80b8 100644
--- a/tests/model_fields/test_filefield.py
+++ b/tests/model_fields/test_filefield.py
@@ -72,7 +72,7 @@ class FileFieldTests(TestCase):
         with self.assertRaises(IntegrityError):
             Document.objects.create(myfile='something.txt')
 
-    @unittest.skipIf(sys.platform.startswith('win'), "Windows doesn't support moving open files.")
+    @unittest.skipIf(sys.platform == 'win32', "Windows doesn't support moving open files.")
     # The file's source and destination must be on the same filesystem.
     @override_settings(MEDIA_ROOT=temp.gettempdir())
     def test_move_temporary_file(self):
diff --git a/tests/staticfiles_tests/test_storage.py b/tests/staticfiles_tests/test_storage.py
index afdf4c1761b..c6f6e4fb4eb 100644
--- a/tests/staticfiles_tests/test_storage.py
+++ b/tests/staticfiles_tests/test_storage.py
@@ -420,7 +420,7 @@ class CustomStaticFilesStorage(storage.StaticFilesStorage):
         super().__init__(*args, **kwargs)
 
 
-@unittest.skipIf(sys.platform.startswith('win'), "Windows only partially supports chmod.")
+@unittest.skipIf(sys.platform == 'win32', "Windows only partially supports chmod.")
 class TestStaticFilePermissions(CollectionTestCase):
 
     command_params = {
diff --git a/tests/template_tests/test_loaders.py b/tests/template_tests/test_loaders.py
index 3c5282a8ea9..258b18fca0a 100644
--- a/tests/template_tests/test_loaders.py
+++ b/tests/template_tests/test_loaders.py
@@ -196,7 +196,7 @@ class FileSystemLoaderTests(SimpleTestCase):
 
     def test_notafile_error(self):
         # Windows raises PermissionError when trying to open a directory.
-        with self.assertRaises(PermissionError if sys.platform.startswith('win') else IsADirectoryError):
+        with self.assertRaises(PermissionError if sys.platform == 'win32' else IsADirectoryError):
             self.engine.get_template('first')
 
 
diff --git a/tests/timezones/tests.py b/tests/timezones/tests.py
index e57e12d6c4f..a317af5a555 100644
--- a/tests/timezones/tests.py
+++ b/tests/timezones/tests.py
@@ -969,7 +969,7 @@ class TemplateTests(SimpleTestCase):
         with self.assertRaises(pytz.UnknownTimeZoneError):
             Template("{% load tz %}{% timezone tz %}{% endtimezone %}").render(Context({'tz': 'foobar'}))
 
-    @skipIf(sys.platform.startswith('win'), "Windows uses non-standard time zone names")
+    @skipIf(sys.platform == 'win32', "Windows uses non-standard time zone names")
     def test_get_current_timezone_templatetag(self):
         """
         Test the {% get_current_timezone %} templatetag.
@@ -1009,7 +1009,7 @@ class TemplateTests(SimpleTestCase):
         with self.assertRaisesMessage(TemplateSyntaxError, msg):
             Template("{% load tz %}{% get_current_timezone %}").render()
 
-    @skipIf(sys.platform.startswith('win'), "Windows uses non-standard time zone names")
+    @skipIf(sys.platform == 'win32', "Windows uses non-standard time zone names")
     def test_tz_template_context_processor(self):
         """
         Test the django.template.context_processors.tz template context processor.