diff --git a/packages/docusaurus-theme-classic/src/theme/Heading/index.tsx b/packages/docusaurus-theme-classic/src/theme/Heading/index.tsx
index 9969fdbb6e55..3bb321285593 100644
--- a/packages/docusaurus-theme-classic/src/theme/Heading/index.tsx
+++ b/packages/docusaurus-theme-classic/src/theme/Heading/index.tsx
@@ -30,6 +30,7 @@ export default function Heading({as: As, id, ...props}: Props): JSX.Element {
         hideOnScroll
           ? styles.anchorWithHideOnScrollNavbar
           : styles.anchorWithStickyNavbar,
+        props.className,
       )}
       id={id}>
       {props.children}