diff --git a/tests/modeltests/timezones/tests.py b/tests/modeltests/timezones/tests.py
index a38e4b3f75..4621f0a60c 100644
--- a/tests/modeltests/timezones/tests.py
+++ b/tests/modeltests/timezones/tests.py
@@ -467,6 +467,7 @@ class NewDatabaseTests(TestCase):
                 [event],
                 transform=lambda d: d)
 
+    @requires_tz_support
     def test_filter_date_field_with_aware_datetime(self):
         # Regression test for #17742
         day = datetime.date(2011, 9, 1)
diff --git a/tests/regressiontests/generic_views/dates.py b/tests/regressiontests/generic_views/dates.py
index 808582a6a5..d18d10e603 100644
--- a/tests/regressiontests/generic_views/dates.py
+++ b/tests/regressiontests/generic_views/dates.py
@@ -1,14 +1,27 @@
 from __future__ import absolute_import
 
+import time
 import datetime
 
 from django.core.exceptions import ImproperlyConfigured
 from django.test import TestCase
 from django.test.utils import override_settings
 from django.utils import timezone
+from django.utils.unittest import skipUnless
 
 from .models import Book, BookSigning
 
+TZ_SUPPORT = hasattr(time, 'tzset')
+
+# On OSes that don't provide tzset (Windows), we can't set the timezone
+# in which the program runs. As a consequence, we must skip tests that
+# don't enforce a specific timezone (with timezone.override or equivalent),
+# or attempt to interpret naive datetimes in the default timezone.
+
+requires_tz_support = skipUnless(TZ_SUPPORT,
+        "This test relies on the ability to run a program in an arbitrary "
+        "time zone, but your operating system isn't able to do that.")
+
 
 class ArchiveIndexViewTests(TestCase):
     fixtures = ['generic-views-test-data.json']
@@ -100,6 +113,7 @@ class ArchiveIndexViewTests(TestCase):
         res = self.client.get('/dates/booksignings/')
         self.assertEqual(res.status_code, 200)
 
+    @requires_tz_support
     @override_settings(USE_TZ=True, TIME_ZONE='Africa/Nairobi')
     def test_aware_datetime_archive_view(self):
         BookSigning.objects.create(event_date=datetime.datetime(2008, 4, 2, 12, 0, tzinfo=timezone.utc))
@@ -502,6 +516,7 @@ class DayArchiveViewTests(TestCase):
         res = self.client.get('/dates/booksignings/2008/apr/2/')
         self.assertEqual(res.status_code, 200)
 
+    @requires_tz_support
     @override_settings(USE_TZ=True, TIME_ZONE='Africa/Nairobi')
     def test_aware_datetime_day_view(self):
         bs = BookSigning.objects.create(event_date=datetime.datetime(2008, 4, 2, 12, 0, tzinfo=timezone.utc))
@@ -578,6 +593,7 @@ class DateDetailViewTests(TestCase):
         res = self.client.get('/dates/booksignings/2008/apr/2/%d/' % bs.pk)
         self.assertEqual(res.status_code, 200)
 
+    @requires_tz_support
     @override_settings(USE_TZ=True, TIME_ZONE='Africa/Nairobi')
     def test_aware_datetime_date_detail(self):
         bs = BookSigning.objects.create(event_date=datetime.datetime(2008, 4, 2, 12, 0, tzinfo=timezone.utc))