diff --git a/packages/components/src/components/post-collapsible/post-collapsible.tsx b/packages/components/src/components/post-collapsible/post-collapsible.tsx
index f99c243af3..424fc8ebbb 100644
--- a/packages/components/src/components/post-collapsible/post-collapsible.tsx
+++ b/packages/components/src/components/post-collapsible/post-collapsible.tsx
@@ -96,7 +96,7 @@ export class PostCollapsible {
 
   render() {
     return (
-      <Host data-version={version} tabIndex={this.collapsed ? -1 : undefined}>
+      <Host data-version={version} tabindex={this.collapsed ? -1 : undefined}>
         <slot />
       </Host>
     );