diff --git a/src/Controllers/AuthController.php b/src/Controllers/AuthController.php
index 4f5edbc0..ddcf2adf 100644
--- a/src/Controllers/AuthController.php
+++ b/src/Controllers/AuthController.php
@@ -17,7 +17,7 @@ class AuthController
 		$config = \Chibi\Registry::getConfig();
 		$context = \Chibi\Registry::getContext();
 
-		$dbUser = R::findOne('user', 'name = ?', [$name]);
+		$dbUser = Model_User::locate($name, false);
 		if ($dbUser === null)
 			throw new SimpleException('Invalid username');
 
diff --git a/src/Models/Model_Post_QueryBuilder.php b/src/Models/Model_Post_QueryBuilder.php
index 8fa0212b..fb11f624 100644
--- a/src/Models/Model_Post_QueryBuilder.php
+++ b/src/Models/Model_Post_QueryBuilder.php
@@ -197,7 +197,7 @@ class Model_Post_QueryBuilder implements AbstractQueryBuilder
 			->innerJoin('user')
 			->on('favoritee.user_id = user.id')
 			->where('post_id = post.id')
-			->and('user.name = ?')->put($val)
+			->and('LOWER(user.name) = LOWER(?)')->put($val)
 			->close();
 	}
 
@@ -226,7 +226,7 @@ class Model_Post_QueryBuilder implements AbstractQueryBuilder
 			->innerJoin('user')
 			->on('commenter_id = user.id')
 			->where('post_id = post.id')
-			->and('user.name = ?')->put($val)
+			->and('LOWER(user.name) = LOWER(?)')->put($val)
 			->close();
 	}
 
@@ -242,7 +242,7 @@ class Model_Post_QueryBuilder implements AbstractQueryBuilder
 			->open()
 			->select('user.id')
 			->from('user')
-			->where('name = ?')->put($val)
+			->where('LOWER(name) = LOWER(?)')->put($val)
 			->close();
 	}
 
diff --git a/src/Models/Model_User.php b/src/Models/Model_User.php
index cbb26098..59c47266 100644
--- a/src/Models/Model_User.php
+++ b/src/Models/Model_User.php
@@ -3,7 +3,7 @@ class Model_User extends AbstractModel
 {
 	public static function locate($key, $throw = true)
 	{
-		$user = R::findOne(self::getTableName(), 'name = ?', [$key]);
+		$user = R::findOne(self::getTableName(), 'LOWER(name) = LOWER(?)', [$key]);
 		if ($user)
 			return $user;
 
@@ -97,7 +97,7 @@ class Model_User extends AbstractModel
 	{
 		$userName = trim($userName);
 
-		$dbUser = R::findOne(self::getTableName(), 'name = ?', [$userName]);
+		$dbUser = R::findOne(self::getTableName(), 'LOWER(name) = LOWER(?)', [$userName]);
 		if ($dbUser !== null)
 		{
 			if (!$dbUser->email_confirmed and \Chibi\Registry::getConfig()->registration->needEmailForRegistering)