diff --git a/packages/docusaurus-theme-classic/src/theme-classic.d.ts b/packages/docusaurus-theme-classic/src/theme-classic.d.ts
index 46322ff38167..f010df9a8515 100644
--- a/packages/docusaurus-theme-classic/src/theme-classic.d.ts
+++ b/packages/docusaurus-theme-classic/src/theme-classic.d.ts
@@ -1072,7 +1072,7 @@ declare module '@theme/NavbarItem/LocaleDropdownNavbarItem' {
   export interface Props extends DropdownNavbarItemProps {
     readonly dropdownItemsBefore: LinkLikeNavbarItemProps[];
     readonly dropdownItemsAfter: LinkLikeNavbarItemProps[];
-    readonly queryString: string;
+    readonly queryString?: string;
   }
 
   export default function LocaleDropdownNavbarItem(props: Props): JSX.Element;