diff --git a/wagtail/contrib/wagtailapi/serializers.py b/wagtail/contrib/wagtailapi/serializers.py
index 433a054e9..388e666e4 100644
--- a/wagtail/contrib/wagtailapi/serializers.py
+++ b/wagtail/contrib/wagtailapi/serializers.py
@@ -56,7 +56,7 @@ class StreamField(Field):
 
 class TagsField(Field):
     def to_representation(self, value):
-        return list(value.all().values_list('name', flat=True))
+        return list(value.all().order_by('name').values_list('name', flat=True))
 
 
 class BaseSerializer(serializers.ModelSerializer):
diff --git a/wagtail/contrib/wagtailapi/tests/test_pages.py b/wagtail/contrib/wagtailapi/tests/test_pages.py
index e7f5c3d31..bb95a8c10 100644
--- a/wagtail/contrib/wagtailapi/tests/test_pages.py
+++ b/wagtail/contrib/wagtailapi/tests/test_pages.py
@@ -586,7 +586,7 @@ class TestPageDetail(TestCase):
         self.assertEqual(content['date'], '2013-12-02')
 
         # Check that the tags were serialised properly
-        self.assertEqual(content['tags'], ['wagtail', 'bird'])
+        self.assertEqual(content['tags'], ['bird', 'wagtail'])
 
         # Check that the feed image was serialised properly
         self.assertIsInstance(content['feed_image'], dict)