diff --git a/wagtail/admin/templatetags/wagtailadmin_tags.py b/wagtail/admin/templatetags/wagtailadmin_tags.py
index 5b9e0bb7f..03f97bcef 100644
--- a/wagtail/admin/templatetags/wagtailadmin_tags.py
+++ b/wagtail/admin/templatetags/wagtailadmin_tags.py
@@ -19,6 +19,7 @@ from wagtail.core.models import (
     CollectionViewRestriction, Page, PageViewRestriction, UserPagePermissionsProxy)
 from wagtail.core.utils import cautious_slugify as _cautious_slugify
 from wagtail.core.utils import camelcase_to_underscore, escape_script
+from wagtail.users.utils import get_gravatar_url
 from wagtail.utils.pagination import DEFAULT_PAGE_KEY, replace_page_in_query
 
 register = template.Library()
@@ -374,14 +375,20 @@ def admin_urlquote(value):
     return quote(value)
 
 
-@register.simple_tag(takes_context=True)
-def avatar_url(context, user, size=50):
+@register.simple_tag
+def avatar_url(user, size=50):
     """
     A template tag that receives a user and size and return
     the appropiate avatar url for that user.
     Example usage: {% avatar_url request.user 50 %}
     """
 
-    if hasattr(user, 'wagtail_userprofile'):  # A user could not have profile yet, so this is necessary
-        return user.wagtail_userprofile.get_avatar_url(size=size)
+    if hasattr(user, 'wagtail_userprofile') and user.wagtail_userprofile.avatar:
+        return user.wagtail_userprofile.avatar.url
+
+    if hasattr(user, 'email'):
+        gravatar_url = get_gravatar_url(user.email, size=size)
+        if gravatar_url is not None:
+            return gravatar_url
+
     return static('wagtailadmin/images/default-user-avatar.png')
diff --git a/wagtail/admin/tests/test_account_management.py b/wagtail/admin/tests/test_account_management.py
index 1359c6d4b..b008f0684 100644
--- a/wagtail/admin/tests/test_account_management.py
+++ b/wagtail/admin/tests/test_account_management.py
@@ -515,11 +515,10 @@ class TestAvatarSection(TestCase, WagtailTestUtils):
         profile = UserProfile.get_for_user(get_user_model().objects.get(pk=self.user.pk))
         self.assertEqual('default', profile.avatar_choice)
 
-    def test_get_avatar_returns_default_if_not_changed(self):
+    def test_avatar_choice_returns_default_if_not_changed(self):
         profile = UserProfile.get_for_user(get_user_model().objects.get(pk=self.user.pk))
 
         self.assertEqual(profile.avatar_choice, 'default')
-        self.assertIn('default-user-avatar', profile.get_avatar_url())
 
     def test_set_gravatar_returns_gravatar(self):
         post_data = {
@@ -530,7 +529,6 @@ class TestAvatarSection(TestCase, WagtailTestUtils):
 
         profile = UserProfile.get_for_user(get_user_model().objects.get(pk=self.user.pk))
         self.assertEqual(profile.avatar_choice, 'gravatar')
-        self.assertIn('www.gravatar.com', profile.get_avatar_url())
 
     @override_settings(MEDIA_ROOT=TMP_MEDIA_ROOT)
     def test_set_custom_avatar_stores_and_get_custom_avatar(self):
@@ -543,7 +541,7 @@ class TestAvatarSection(TestCase, WagtailTestUtils):
 
         profile = UserProfile.get_for_user(get_user_model().objects.get(pk=self.user.pk))
         self.assertEqual('custom', profile.avatar_choice)
-        self.assertIn(os.path.basename(self.avatar.name), profile.get_avatar_url())
+        self.assertIn(os.path.basename(self.avatar.name), profile.avatar.url)
 
     @override_settings(MEDIA_ROOT=TMP_MEDIA_ROOT)
     def test_user_upload_another_image_removes_previous_one(self):
diff --git a/wagtail/admin/tests/test_templatetags.py b/wagtail/admin/tests/test_templatetags.py
new file mode 100644
index 000000000..265c39051
--- /dev/null
+++ b/wagtail/admin/tests/test_templatetags.py
@@ -0,0 +1,44 @@
+from django.contrib.auth import get_user_model
+from django.test import TestCase
+from django.test.utils import override_settings
+
+from wagtail.admin.templatetags.wagtailadmin_tags import avatar_url
+from wagtail.images.tests.utils import get_test_image_file
+from wagtail.users.models import UserProfile
+
+
+class TestAvatarTemplateTag(TestCase):
+    def setUp(self):
+        # Create a user
+        self.test_user = get_user_model().objects.create_user(
+            username='testuser',
+            email='testuser@email.com',
+            password='password',
+        )
+
+    def test_use_gravatar_by_default(self):
+        url = avatar_url(self.test_user)
+        self.assertIn('www.gravatar.com', url)
+
+    def test_skip_gravatar_if_no_email(self):
+        self.test_user.email = ''
+        url = avatar_url(self.test_user)
+        self.assertIn('default-user-avatar', url)
+
+    @override_settings(WAGTAIL_GRAVATAR_PROVIDER_URL='https://robohash.org')
+    def test_custom_gravatar_provider(self):
+        url = avatar_url(self.test_user)
+        self.assertIn('robohash.org', url)
+
+    @override_settings(WAGTAIL_GRAVATAR_PROVIDER_URL=None)
+    def test_disable_gravatar(self):
+        url = avatar_url(self.test_user)
+        self.assertIn('default-user-avatar', url)
+
+    def test_uploaded_avatar(self):
+        user_profile = UserProfile.get_for_user(self.test_user)
+        user_profile.avatar = get_test_image_file(filename='custom-avatar.png')
+        user_profile.save()
+
+        url = avatar_url(self.test_user)
+        self.assertIn('custom-avatar', url)
diff --git a/wagtail/users/models.py b/wagtail/users/models.py
index b5c545b8a..b9ae805a9 100644
--- a/wagtail/users/models.py
+++ b/wagtail/users/models.py
@@ -7,8 +7,6 @@ from django.db import models
 from django.utils.functional import cached_property
 from django.utils.translation import ugettext_lazy as _
 
-from wagtail.users.utils import get_gravatar_url
-
 
 def upload_avatar_to(instance, filename):
     filename, ext = os.path.splitext(filename)
@@ -95,21 +93,6 @@ class UserProfile(models.Model):
     def default_avatar(self):
         return static('wagtailadmin/images/default-user-avatar.png')
 
-    def get_avatar_url(self, size=50):
-        if self.avatar_choice == self.DEFAULT:
-            return self.default_avatar
-
-        if self.avatar_choice == self.CUSTOM:
-            try:
-                return self.avatar.url
-            except ValueError:
-                return self.default_avatar
-
-        if self.avatar_choice == self.GRAVATAR and self.user.email:
-            return get_gravatar_url(self.user.email, size=50)
-
-        return self.default_avatar
-
     def save(self, *args, **kwargs):
         if self.avatar:
             this = UserProfile.objects.get(pk=self.pk)
diff --git a/wagtail/users/tests.py b/wagtail/users/tests.py
index 9b5127865..316a3b0b7 100644
--- a/wagtail/users/tests.py
+++ b/wagtail/users/tests.py
@@ -949,12 +949,6 @@ class TestUserProfileCreation(TestCase, WagtailTestUtils):
     def test_get_avatar_url_default(self):
         user_profile = UserProfile.get_for_user(self.test_user)
         self.assertEqual(user_profile.avatar_choice, 'default')
-        self.assertIn('default-user-avatar', user_profile.get_avatar_url())
-
-    def test_get_avatar_url_fallback_default(self):
-        user_profile = UserProfile.get_for_user(self.test_user)
-        user_profile.avatar_choice = 'Non-existent'
-        self.assertIn('default-user-avatar', user_profile.get_avatar_url())
 
 
 class TestUserEditViewForNonSuperuser(TestCase, WagtailTestUtils):
diff --git a/wagtail/users/utils.py b/wagtail/users/utils.py
index 3cbafbff5..d6af40ab0 100644
--- a/wagtail/users/utils.py
+++ b/wagtail/users/utils.py
@@ -1,6 +1,5 @@
 import hashlib
 from django.conf import settings
-from django.contrib.staticfiles.templatetags.staticfiles import static
 from django.utils.http import urlencode
 
 from wagtail.core.compat import AUTH_USER_APP_LABEL, AUTH_USER_MODEL_NAME
@@ -28,8 +27,8 @@ def get_gravatar_url(email, size=50):
     size = int(size) * 2  # requested at retina size by default and scaled down at point of use with css
     gravatar_provider_url = getattr(settings, 'WAGTAIL_GRAVATAR_PROVIDER_URL', '//www.gravatar.com/avatar')
 
-    if gravatar_provider_url is None:
-        return static('wagtailadmin/images/default-user-avatar.png')
+    if (not email) or (gravatar_provider_url is None):
+        return None
 
     gravatar_url = "{gravatar_provider_url}/{hash}?{params}".format(
         gravatar_provider_url=gravatar_provider_url.rstrip('/'),