diff --git a/lib/api/controllers/users/updateUser.ts b/lib/api/controllers/users/updateUser.ts
index cdf6260..8f4eb0f 100644
--- a/lib/api/controllers/users/updateUser.ts
+++ b/lib/api/controllers/users/updateUser.ts
@@ -22,7 +22,7 @@ export default async function updateUser(
 
   const checkUsername = RegExp("^[a-z0-9_-]{3,31}$");
 
-  if (!checkUsername.test(user.username))
+  if (!checkUsername.test(user.username.toLowerCase()))
     return {
       response:
         "Username has to be between 3-30 characters, no spaces and special characters are allowed.",
diff --git a/pages/api/auth/register.ts b/pages/api/auth/register.ts
index 4abf03e..c7e5136 100644
--- a/pages/api/auth/register.ts
+++ b/pages/api/auth/register.ts
@@ -33,7 +33,7 @@ export default async function Index(
 
   const checkUsername = RegExp("^[a-z0-9_-]{3,31}$");
 
-  if (!emailEnabled && !checkUsername.test(body.username || ""))
+  if (!emailEnabled && !checkUsername.test(body.username?.toLowerCase() || ""))
     return res.status(400).json({
       response:
         "Username has to be between 3-30 characters, no spaces and special characters are allowed.",