diff --git a/packages/@vuepress/types/src/theme-default.ts b/packages/@vuepress/types/src/theme-default.ts
index c086041e2a..bc55cd7446 100644
--- a/packages/@vuepress/types/src/theme-default.ts
+++ b/packages/@vuepress/types/src/theme-default.ts
@@ -84,7 +84,7 @@ export type SidebarItem4Group = {
   /**
    * Sidebar children.
    */
-  children?: Array<SidebarItem4Shortcut>;
+  children?: Array<SidebarItem4Shortcut | SidebarItem4Group>;
 };
 
 /**