diff --git a/index.d.ts b/index.d.ts
index 6bc4169..d2a705c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -168,7 +168,7 @@ declare namespace OAuth2Server {
         /**
          * The scope(s) to authenticate.
          */
-        scope?: string[] | undefined;
+        scope?: string | undefined;
 
         /**
          * Set the X-Accepted-OAuth-Scopes HTTP header on response objects.