diff --git a/.changeset/beige-timers-itch.md b/.changeset/beige-timers-itch.md
new file mode 100644
index 0000000000..4fe8eabf22
--- /dev/null
+++ b/.changeset/beige-timers-itch.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/sitemap': minor
+---
+
+Add .html extension to urls if build.format is set to file