diff --git a/src/League/OAuth2/Server/Grant/ClientCredentials.php b/src/League/OAuth2/Server/Grant/ClientCredentials.php
index 363dfb53..3d962ee9 100644
--- a/src/League/OAuth2/Server/Grant/ClientCredentials.php
+++ b/src/League/OAuth2/Server/Grant/ClientCredentials.php
@@ -163,7 +163,7 @@ class ClientCredentials implements GrantTypeInterface {
 
         $response = array(
             'access_token'  =>  $accessToken,
-            'token_type'    =>  'bearer',
+            'token_type'    =>  'Bearer',
             'expires'       =>  $accessTokenExpires,
             'expires_in'    =>  $accessTokenExpiresIn
         );