diff --git a/wagtail/wagtailadmin/tests/tests.py b/wagtail/wagtailadmin/tests/tests.py
index ab3ae83a9..e7cf405c1 100644
--- a/wagtail/wagtailadmin/tests/tests.py
+++ b/wagtail/wagtailadmin/tests/tests.py
@@ -1,7 +1,11 @@
+import json
+
 from django.test import TestCase, override_settings
 from django.core.urlresolvers import reverse
 from django.core import mail
 
+from taggit.models import Tag
+
 from wagtail.tests.utils import WagtailTestUtils
 from wagtail.wagtailcore.models import Page
 from wagtail.wagtailadmin.utils import send_mail
@@ -112,3 +116,51 @@ class TestExplorerNavView(TestCase, WagtailTestUtils):
         self.assertEqual(response.status_code, 200)
         self.assertTemplateUsed('wagtailadmin/shared/explorer_nav.html')
         self.assertEqual(response.context['nodes'][0][0], self.homepage)
+
+
+class TestTagsAutocomplete(TestCase, WagtailTestUtils):
+    def setUp(self):
+        self.login()
+        Tag.objects.create(name="Test", slug="test")
+
+    def test_tags_autocomplete(self):
+        response = self.client.get(reverse('wagtailadmin_tag_autocomplete'), {
+            'term': 'test'
+        })
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response['Content-Type'], 'application/json')
+        data = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(data, ['Test'])
+
+    def test_tags_autocomplete_partial_match(self):
+        response = self.client.get(reverse('wagtailadmin_tag_autocomplete'), {
+            'term': 'te'
+        })
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response['Content-Type'], 'application/json')
+        data = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(data, ['Test'])
+
+    def test_tags_autocomplete_different_term(self):
+        response = self.client.get(reverse('wagtailadmin_tag_autocomplete'), {
+            'term': 'hello'
+        })
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response['Content-Type'], 'application/json')
+        data = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(data, [])
+
+    def test_tags_autocomplete_no_term(self):
+        response = self.client.get(reverse('wagtailadmin_tag_autocomplete'))
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response['Content-Type'], 'application/json')
+        data = json.loads(response.content.decode('utf-8'))
+
+        self.assertEqual(data, [])
diff --git a/wagtail/wagtailadmin/views/tags.py b/wagtail/wagtailadmin/views/tags.py
index 552f3d33e..db1fbafcf 100644
--- a/wagtail/wagtailadmin/views/tags.py
+++ b/wagtail/wagtailadmin/views/tags.py
@@ -10,4 +10,4 @@ def autocomplete(request):
     else:
         tags = Tag.objects.none()
 
-    return JsonResponse([tag.name for tag in tags])
+    return JsonResponse([tag.name for tag in tags], safe=False)