diff --git a/common/djangoapps/enrollment/tests/test_views.py b/common/djangoapps/enrollment/tests/test_views.py
index 5ed7180637..0b4adbc738 100644
--- a/common/djangoapps/enrollment/tests/test_views.py
+++ b/common/djangoapps/enrollment/tests/test_views.py
@@ -115,7 +115,23 @@ class EnrollmentTest(ModuleStoreTestCase, APITestCase):
 
         # Try to enroll, this should fail.
         resp = self.client.post(reverse('courseenrollment', kwargs={'course_id': (unicode(self.course.id))}))
-        self.assertEqual(resp.status_code, status.HTTP_401_UNAUTHORIZED)
+        self.assertEqual(resp.status_code, status.HTTP_403_FORBIDDEN)
+
+    def test_user_not_activated(self):
+        # Create a user account, but don't activate it
+        self.user = UserFactory.create(
+            username="inactive",
+            email="inactive@example.com",
+            password=self.PASSWORD,
+            is_active=False
+        )
+
+        # Log in with the unactivated account
+        self.client.login(username="inactive", password=self.PASSWORD)
+
+        # Enrollment should succeed, even though we haven't authenticated.
+        resp = self.client.post(reverse('courseenrollment', kwargs={'course_id': (unicode(self.course.id))}))
+        self.assertEqual(resp.status_code, 200)
 
     def test_unenroll_not_enrolled_in_course(self):
         # Deactivate the enrollment in the course and verify the URL we get sent to
diff --git a/common/djangoapps/enrollment/views.py b/common/djangoapps/enrollment/views.py
index c2e401dd35..35a3fc603d 100644
--- a/common/djangoapps/enrollment/views.py
+++ b/common/djangoapps/enrollment/views.py
@@ -17,6 +17,52 @@ class EnrollmentUserThrottle(UserRateThrottle):
     rate = '50/second'  # TODO Limit significantly after performance testing.
 
 
+class SessionAuthenticationAllowInactiveUser(SessionAuthentication):
+    """Ensure that the user is logged in, but do not require the account to be active.
+
+    We use this in the special case that a user has created an account,
+    but has not yet activated it.  We still want to allow the user to
+    enroll in courses, so we remove the usual restriction
+    on session authentication that requires an active account.
+
+    You should use this authentication class ONLY for end-points that
+    it's safe for an unactived user to access.  For example,
+    we can allow a user to update his/her own enrollments without
+    activating an account.
+
+    """
+    def authenticate(self, request):
+        """Authenticate the user, requiring a logged-in account and CSRF.
+
+        This is exactly the same as the `SessionAuthentication` implementation,
+        with the `user.is_active` check removed.
+
+        Args:
+            request (HttpRequest)
+
+        Returns:
+            Tuple of `(user, token)`
+
+        Raises:
+            PermissionDenied: The CSRF token check failed.
+
+        """
+        # Get the underlying HttpRequest object
+        request = request._request
+        user = getattr(request, 'user', None)
+
+        # Unauthenticated, CSRF validation not required
+        # This is where regular `SessionAuthentication` checks that the user is active.
+        # We have removed that check in this implementation.
+        if not user:
+            return None
+
+        self.enforce_csrf(request)
+
+        # CSRF passed with authenticated user
+        return (user, None)
+
+
 @api_view(['GET'])
 @authentication_classes((OAuth2Authentication, SessionAuthentication))
 @permission_classes((IsAuthenticated,))
@@ -37,7 +83,7 @@ def list_student_enrollments(request):
 
 
 @api_view(['GET', 'POST'])
-@authentication_classes((OAuth2Authentication, SessionAuthentication))
+@authentication_classes((OAuth2Authentication, SessionAuthenticationAllowInactiveUser))
 @permission_classes((IsAuthenticated,))
 @throttle_classes([EnrollmentUserThrottle])
 def get_course_enrollment(request, course_id=None):