diff --git a/defender/tests.py b/defender/tests.py
index 43eb4fb..bb62c26 100644
--- a/defender/tests.py
+++ b/defender/tests.py
@@ -31,6 +31,7 @@ ADMIN_LOGIN_URL = reverse('admin:login')
 DJANGO_VERSION = StrictVersion(get_version())
 
 VALID_USERNAME = VALID_PASSWORD = 'valid'
+UPPER_USERNAME = 'VALID'
 
 
 class AccessAttemptTest(DefenderTestCase):
@@ -210,6 +211,18 @@ class AccessAttemptTest(DefenderTestCase):
         response = self._login(username=VALID_USERNAME, remote_addr='8.8.8.8')
         self.assertContains(response, self.LOCKED_MESSAGE)
 
+    def test_blocked_username_uppercase_saved_lower(self):
+        """
+        Test that a uppercase username is saved in lowercase
+        within the cache.
+        """
+        for i in range(0, config.FAILURE_LIMIT + 2):
+            ip = '74.125.239.{0}.'.format(i)
+            self._login(username=UPPER_USERNAME, remote_addr=ip)
+
+        self.assertNotIn(UPPER_USERNAME, utils.get_blocked_usernames())
+        self.assertIn(UPPER_USERNAME.lower(), utils.get_blocked_usernames())
+
     def test_cooling_off(self):
         """ Tests if the cooling time allows a user to login
         """
diff --git a/defender/utils.py b/defender/utils.py
index 9da01af..36e6676 100644
--- a/defender/utils.py
+++ b/defender/utils.py
@@ -48,6 +48,16 @@ def get_ip(request):
     return ip_address
 
 
+def lower_username(username):
+    """
+    Single entry point to force the username to lowercase, all the functions
+    that need to deal with username should call this.
+    """
+    if username:
+        return username.lower()
+    return None
+
+
 def get_ip_attempt_cache_key(ip_address):
     """ get the cache key by ip """
     return "{0}:failed:ip:{1}".format(config.CACHE_PREFIX, ip_address)
@@ -55,7 +65,8 @@ def get_ip_attempt_cache_key(ip_address):
 
 def get_username_attempt_cache_key(username):
     """ get the cache key by username """
-    return "{0}:failed:username:{1}".format(config.CACHE_PREFIX, username)
+    return "{0}:failed:username:{1}".format(config.CACHE_PREFIX,
+                                            lower_username(username))
 
 
 def get_ip_blocked_cache_key(ip_address):
@@ -65,7 +76,8 @@ def get_ip_blocked_cache_key(ip_address):
 
 def get_username_blocked_cache_key(username):
     """ get the cache key by username """
-    return "{0}:blocked:username:{1}".format(config.CACHE_PREFIX, username)
+    return "{0}:blocked:username:{1}".format(config.CACHE_PREFIX,
+                                             lower_username(username))
 
 
 def strip_keys(key_list):
@@ -128,7 +140,7 @@ def get_user_attempts(request, get_username=get_username_from_request):
     """
     ip_address = get_ip(request)
 
-    username = get_username(request)
+    username = lower_username(get_username(request))
 
     # get by IP
     ip_count = REDIS_SERVER.get(get_ip_attempt_cache_key(ip_address))