diff --git a/index.d.ts b/index.d.ts
index b95bffa..e6e5827 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -6,4 +6,7 @@ declare global {
   interface Window {
     MarkdownToolbarElement: typeof MarkdownToolbarElement
   }
-}
+  interface HTMLElementTagNameMap {
+    'markdown-toolbar': MarkdownToolbarElement
+  }
+}
\ No newline at end of file