diff --git a/lib/OAuth2.php b/lib/OAuth2.php
index 31da279..1e1e76a 100644
--- a/lib/OAuth2.php
+++ b/lib/OAuth2.php
@@ -890,7 +890,7 @@ protected function grantAccessTokenAuthCode(IOAuth2Client $client, array $input)
 
         // Validate the redirect URI. If a redirect URI has been provided on input, it must be validated
         if ($input["redirect_uri"] && !$this->validateRedirectUri(
-                $input["redirect_uri"],
+                urldecode($input["redirect_uri"]),
                 $authCode->getRedirectUri()
             )
         ) {