diff --git a/.changeset/neat-pumas-accept.md b/.changeset/neat-pumas-accept.md
new file mode 100644
index 000000000000..8babf49e78ff
--- /dev/null
+++ b/.changeset/neat-pumas-accept.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Adds type support for the `closedby` attribute for `<dialog>` elements
diff --git a/packages/astro/astro-jsx.d.ts b/packages/astro/astro-jsx.d.ts
index ca54b991ed5a..39cb40f61bd4 100644
--- a/packages/astro/astro-jsx.d.ts
+++ b/packages/astro/astro-jsx.d.ts
@@ -679,6 +679,7 @@ declare namespace astroHTML.JSX {
 
 	interface DialogHTMLAttributes extends HTMLAttributes {
 		open?: boolean | string | undefined | null;
+		closedby?: 'none' | 'closerequest' | 'any' | undefined | null;
 	}
 
 	interface EmbedHTMLAttributes extends HTMLAttributes {