diff --git a/django/contrib/auth/backends.py b/django/contrib/auth/backends.py
index db99c94..703fd25 100644
--- a/django/contrib/auth/backends.py
+++ b/django/contrib/auth/backends.py
@@ -13,7 +13,7 @@ class ModelBackend(object):
     def authenticate(self, username=None, password=None):
         try:
             UserModel = get_user_model()
-            user = UserModel.objects.get_by_natural_key(username)
+            user = UserModel._default_manager.get_by_natural_key(username)
             if user.check_password(password):
                 return user
         except UserModel.DoesNotExist:
@@ -64,7 +64,7 @@ class ModelBackend(object):
     def get_user(self, user_id):
         try:
             UserModel = get_user_model()
-            return UserModel.objects.get(pk=user_id)
+            return UserModel._default_manager.get(pk=user_id)
         except UserModel.DoesNotExist:
             return None
 
diff --git a/django/contrib/auth/forms.py b/django/contrib/auth/forms.py
index 8529112..cbce8ad 100644
--- a/django/contrib/auth/forms.py
+++ b/django/contrib/auth/forms.py
@@ -89,7 +89,7 @@ class UserCreationForm(forms.ModelForm):
         # but it sets a nicer error message than the ORM. See #13147.
         username = self.cleaned_data["username"]
         try:
-            User.objects.get(username=username)
+            User._default_manager.get(username=username)
         except User.DoesNotExist:
             return username
         raise forms.ValidationError(self.error_messages['duplicate_username'])
@@ -217,7 +217,7 @@ class PasswordResetForm(forms.Form):
         """
         UserModel = get_user_model()
         email = self.cleaned_data["email"]
-        self.users_cache = UserModel.objects.filter(email__iexact=email)
+        self.users_cache = UserModel._default_manager.filter(email__iexact=email)
         if not len(self.users_cache):
             raise forms.ValidationError(self.error_messages['unknown'])
         if not any(user.is_active for user in self.users_cache):
diff --git a/django/contrib/auth/handlers/modwsgi.py b/django/contrib/auth/handlers/modwsgi.py
index 5ee4d60..a26d621 100644
--- a/django/contrib/auth/handlers/modwsgi.py
+++ b/django/contrib/auth/handlers/modwsgi.py
@@ -18,7 +18,7 @@ def check_password(environ, username, password):
 
     try:
         try:
-            user = UserModel.objects.get_by_natural_key(username)
+            user = UserModel._default_manager.get_by_natural_key(username)
         except UserModel.DoesNotExist:
             return None
         if not user.is_active:
@@ -37,7 +37,7 @@ def groups_for_user(environ, username):
 
     try:
         try:
-            user = UserModel.objects.get_by_natural_key(username)
+            user = UserModel._default_manager.get_by_natural_key(username)
         except UserModel.DoesNotExist:
             return []
         try:
diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index ce5d57f..a77bba0 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -174,7 +174,7 @@ def get_default_username(check_db=True):
     # Don't return the default username if it is already taken.
     if check_db and default_username:
         try:
-            auth_app.User.objects.get(username=default_username)
+            auth_app.User._default_manager.get(username=default_username)
         except auth_app.User.DoesNotExist:
             pass
         else:
diff --git a/django/contrib/auth/management/commands/changepassword.py b/django/contrib/auth/management/commands/changepassword.py
index ff38836..3240b0f 100644
--- a/django/contrib/auth/management/commands/changepassword.py
+++ b/django/contrib/auth/management/commands/changepassword.py
@@ -33,7 +33,7 @@ class Command(BaseCommand):
         UserModel = get_user_model()
 
         try:
-            u = UserModel.objects.using(options.get('database')).get(**{
+            u = UserModel._default_manager.using(options.get('database')).get(**{
                     UserModel.USERNAME_FIELD: username
                 })
         except UserModel.DoesNotExist:
diff --git a/django/contrib/auth/management/commands/createsuperuser.py b/django/contrib/auth/management/commands/createsuperuser.py
index 216d56d..7b4764a 100644
--- a/django/contrib/auth/management/commands/createsuperuser.py
+++ b/django/contrib/auth/management/commands/createsuperuser.py
@@ -95,7 +95,7 @@ class Command(BaseCommand):
                         username = None
                         continue
                     try:
-                        self.UserModel.objects.db_manager(database).get_by_natural_key(username)
+                        self.UserModel._default_manager.db_manager(database).get_by_natural_key(username)
                     except self.UserModel.DoesNotExist:
                         pass
                     else:
@@ -134,6 +134,6 @@ class Command(BaseCommand):
 
         user_data[self.UserModel.USERNAME_FIELD] = username
         user_data['password'] = password
-        self.UserModel.objects.db_manager(database).create_superuser(**user_data)
+        self.UserModel._default_manager.db_manager(database).create_superuser(**user_data)
         if verbosity >= 1:
             self.stdout.write("Superuser created successfully.")
diff --git a/django/contrib/auth/tests/auth_backends.py b/django/contrib/auth/tests/auth_backends.py
index 71f18d3..074374c 100644
--- a/django/contrib/auth/tests/auth_backends.py
+++ b/django/contrib/auth/tests/auth_backends.py
@@ -34,7 +34,7 @@ class BaseModelBackendTest(object):
         ContentType.objects.clear_cache()
 
     def test_has_perm(self):
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         self.assertEqual(user.has_perm('auth.test'), False)
         user.is_staff = True
         user.save()
@@ -53,14 +53,14 @@ class BaseModelBackendTest(object):
         self.assertEqual(user.has_perm('auth.test'), False)
 
     def test_custom_perms(self):
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         content_type = ContentType.objects.get_for_model(Group)
         perm = Permission.objects.create(name='test', content_type=content_type, codename='test')
         user.user_permissions.add(perm)
         user.save()
 
         # reloading user to purge the _perm_cache
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         self.assertEqual(user.get_all_permissions() == set(['auth.test']), True)
         self.assertEqual(user.get_group_permissions(), set([]))
         self.assertEqual(user.has_module_perms('Group'), False)
@@ -71,7 +71,7 @@ class BaseModelBackendTest(object):
         perm = Permission.objects.create(name='test3', content_type=content_type, codename='test3')
         user.user_permissions.add(perm)
         user.save()
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         self.assertEqual(user.get_all_permissions(), set(['auth.test2', 'auth.test', 'auth.test3']))
         self.assertEqual(user.has_perm('test'), False)
         self.assertEqual(user.has_perm('auth.test'), True)
@@ -81,7 +81,7 @@ class BaseModelBackendTest(object):
         group.permissions.add(perm)
         group.save()
         user.groups.add(group)
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         exp = set(['auth.test2', 'auth.test', 'auth.test3', 'auth.test_group'])
         self.assertEqual(user.get_all_permissions(), exp)
         self.assertEqual(user.get_group_permissions(), set(['auth.test_group']))
@@ -93,7 +93,7 @@ class BaseModelBackendTest(object):
 
     def test_has_no_object_perm(self):
         """Regressiontest for #12462"""
-        user = self.UserModel.objects.get(pk=self.user.pk)
+        user = self.UserModel._default_manager.get(pk=self.user.pk)
         content_type = ContentType.objects.get_for_model(Group)
         perm = Permission.objects.create(name='test', content_type=content_type, codename='test')
         user.user_permissions.add(perm)
@@ -106,7 +106,7 @@ class BaseModelBackendTest(object):
 
     def test_get_all_superuser_permissions(self):
         "A superuser has all permissions. Refs #14795"
-        user = self.UserModel.objects.get(pk=self.superuser.pk)
+        user = self.UserModel._default_manager.get(pk=self.superuser.pk)
         self.assertEqual(len(user.get_all_permissions()), len(Permission.objects.all()))
 
 
@@ -151,13 +151,13 @@ class ExtensionUserModelBackendTest(BaseModelBackendTest, TestCase):
     UserModel = ExtensionUser
 
     def create_users(self):
-        self.user = ExtensionUser.objects.create_user(
+        self.user = ExtensionUser._default_manager.create_user(
             username='test',
             email='test@example.com',
             password='test',
             date_of_birth=date(2006, 4, 25)
         )
-        self.superuser = ExtensionUser.objects.create_superuser(
+        self.superuser = ExtensionUser._default_manager.create_superuser(
             username='test2',
             email='test2@example.com',
             password='test',
@@ -178,12 +178,12 @@ class CustomPermissionsUserModelBackendTest(BaseModelBackendTest, TestCase):
     UserModel = CustomPermissionsUser
 
     def create_users(self):
-        self.user = CustomPermissionsUser.objects.create_user(
+        self.user = CustomPermissionsUser._default_manager.create_user(
             email='test@example.com',
             password='test',
             date_of_birth=date(2006, 4, 25)
         )
-        self.superuser = CustomPermissionsUser.objects.create_superuser(
+        self.superuser = CustomPermissionsUser._default_manager.create_superuser(
             email='test2@example.com',
             password='test',
             date_of_birth=date(1976, 11, 8)
diff --git a/django/contrib/auth/tests/custom_user.py b/django/contrib/auth/tests/custom_user.py
index 7e042e4..8cc57d4 100644
--- a/django/contrib/auth/tests/custom_user.py
+++ b/django/contrib/auth/tests/custom_user.py
@@ -42,7 +42,7 @@ class CustomUser(AbstractBaseUser):
     is_admin = models.BooleanField(default=False)
     date_of_birth = models.DateField()
 
-    objects = CustomUserManager()
+    custom_objects = CustomUserManager()
 
     USERNAME_FIELD = 'email'
     REQUIRED_FIELDS = ['date_of_birth']
@@ -88,7 +88,7 @@ class CustomUser(AbstractBaseUser):
 class ExtensionUser(AbstractUser):
     date_of_birth = models.DateField()
 
-    objects = UserManager()
+    custom_objects = UserManager()
 
     REQUIRED_FIELDS = AbstractUser.REQUIRED_FIELDS + ['date_of_birth']
 
@@ -112,7 +112,7 @@ class CustomPermissionsUser(AbstractBaseUser, PermissionsMixin):
     email = models.EmailField(verbose_name='email address', max_length=255, unique=True)
     date_of_birth = models.DateField()
 
-    objects = CustomPermissionsUserManager()
+    custom_objects = CustomPermissionsUserManager()
 
     USERNAME_FIELD = 'email'
     REQUIRED_FIELDS = ['date_of_birth']
@@ -136,7 +136,7 @@ class IsActiveTestUser1(AbstractBaseUser):
     """
     username = models.CharField(max_length=30, unique=True)
 
-    objects = BaseUserManager()
+    custom_objects = BaseUserManager()
 
     USERNAME_FIELD = 'username'
 
diff --git a/django/contrib/auth/tests/handlers.py b/django/contrib/auth/tests/handlers.py
index 04ab46f..41063aa 100644
--- a/django/contrib/auth/tests/handlers.py
+++ b/django/contrib/auth/tests/handlers.py
@@ -42,7 +42,7 @@ class ModWsgiHandlerTestCase(TransactionTestCase):
         with custom user installed
         """
 
-        CustomUser.objects.create_user('test@example.com', '1990-01-01', 'test')
+        CustomUser._default_manager.create_user('test@example.com', '1990-01-01', 'test')
 
         # User not in database
         self.assertTrue(check_password({}, 'unknown', '') is None)
diff --git a/django/contrib/auth/tests/management.py b/django/contrib/auth/tests/management.py
index 02939e3..42f14d6 100644
--- a/django/contrib/auth/tests/management.py
+++ b/django/contrib/auth/tests/management.py
@@ -125,7 +125,7 @@ class CreatesuperuserManagementCommandTestCase(TestCase):
             email="joe@somewhere.org",
             stdout=new_io
         )
-        u = User.objects.get(username="joe+admin@somewhere.org")
+        u = User._default_manager.get(username="joe+admin@somewhere.org")
         self.assertEqual(u.email, 'joe@somewhere.org')
         self.assertFalse(u.has_usable_password())
 
@@ -145,7 +145,7 @@ class CreatesuperuserManagementCommandTestCase(TestCase):
         )
         command_output = new_io.getvalue().strip()
         self.assertEqual(command_output, 'Superuser created successfully.')
-        u = CustomUser.objects.get(email="joe@somewhere.org")
+        u = CustomUser._default_manager.get(email="joe@somewhere.org")
         self.assertEqual(u.date_of_birth, date(1976, 4, 1))
 
         # created password should be unusable
@@ -167,7 +167,7 @@ class CreatesuperuserManagementCommandTestCase(TestCase):
                 skip_validation=True
             )
 
-        self.assertEqual(CustomUser.objects.count(), 0)
+        self.assertEqual(CustomUser._default_manager.count(), 0)
 
 
 class PermissionDuplicationTestCase(TestCase):
diff --git a/django/contrib/auth/tests/models.py b/django/contrib/auth/tests/models.py
index da0e45a..8ac0599 100644
--- a/django/contrib/auth/tests/models.py
+++ b/django/contrib/auth/tests/models.py
@@ -137,6 +137,6 @@ class IsActiveTestCase(TestCase):
         user.is_active = False
         # there should be no problem saving - but the attribute is not saved
         user.save()
-        user_fetched = UserModel.objects.get(pk=user.pk)
+        user_fetched = UserModel._default_manager.get(pk=user.pk)
         # the attribute is always true for newly retrieved instance
         self.assertEqual(user_fetched.is_active, True)
diff --git a/django/contrib/auth/views.py b/django/contrib/auth/views.py
index 8514345..9d15346 100644
--- a/django/contrib/auth/views.py
+++ b/django/contrib/auth/views.py
@@ -200,7 +200,7 @@ def password_reset_confirm(request, uidb36=None, token=None,
         post_reset_redirect = reverse('django.contrib.auth.views.password_reset_complete')
     try:
         uid_int = base36_to_int(uidb36)
-        user = UserModel.objects.get(pk=uid_int)
+        user = UserModel._default_manager.get(pk=uid_int)
     except (ValueError, OverflowError, UserModel.DoesNotExist):
         user = None
 
