diff --git a/organizations/backends.py b/organizations/backends.py
index e23d6a36..4d0164cd 100644
--- a/organizations/backends.py
+++ b/organizations/backends.py
@@ -70,25 +70,3 @@ def authenticate(self, *args, **kwargs):  # pylint: disable=arguments-differ
             if site_organization in user_organizations:
                 return user
         return None
-
-
-class SiteMemberBackend(ModelBackend):
-    """
-    Extension of the regular ModelBackend that will check whether the user is a member of the currently
-    active site.
-
-    Deprecated: Should be removed because `UserSiteMapping` should be removed.
-    """
-
-    def authenticate(self, *args, **kwargs):  # pylint: disable=arguments-differ
-        """
-        Authenticate organization learners.
-        """
-        user = super(SiteMemberBackend, self).authenticate(*args, **kwargs)
-        # superuser can log into any microsite
-        site = get_current_site()
-        is_default_site = site.id == settings.SITE_ID
-        if not is_default_site and is_site_configuration_enabled() and user and not user.is_superuser:
-            if user.id in site.usersitemapping_set.select_related('user').values_list('user__id', flat=True):
-                return user
-        return None
diff --git a/organizations/migrations/0012_delete_usersitemapping.py b/organizations/migrations/0012_delete_usersitemapping.py
new file mode 100644
index 00000000..bc081192
--- /dev/null
+++ b/organizations/migrations/0012_delete_usersitemapping.py
@@ -0,0 +1,16 @@
+# Generated by Django 2.2.12 on 2021-06-02 06:38
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('organizations', '0011_historicalorganization_edx_uuid'),
+    ]
+
+    operations = [
+        migrations.DeleteModel(
+            name='UserSiteMapping',
+        ),
+    ]
diff --git a/organizations/models.py b/organizations/models.py
index 1109aa52..686847e4 100644
--- a/organizations/models.py
+++ b/organizations/models.py
@@ -121,16 +121,3 @@ def __str__(self):
             email=self.user.email,  # pylint: disable=no-member
             organization=org.short_name,
         )
-
-
-class UserSiteMapping(models.Model):
-    """
-    User membership in a site.
-
-    Deprecated: Not used by Tahoe. Should be removed.
-    """
-
-    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
-    site = models.ForeignKey(Site, on_delete=models.CASCADE)
-    is_active = models.BooleanField(default=True)
-    is_amc_admin = models.BooleanField(default=False)