diff --git a/.changeset/yellow-poems-live.md b/.changeset/yellow-poems-live.md
new file mode 100644
index 00000000..599704f4
--- /dev/null
+++ b/.changeset/yellow-poems-live.md
@@ -0,0 +1,5 @@
+---
+'mp4box': minor
+---
+
+Read altt item property
diff --git a/entries/all-boxes.ts b/entries/all-boxes.ts
index 6fc77045..6250bfa5 100644
--- a/entries/all-boxes.ts
+++ b/entries/all-boxes.ts
@@ -137,6 +137,7 @@ export * from '#/boxes/tsel';
 export * from '#/boxes/txtC';
 export * from '#/boxes/tyco';
 export * from '#/boxes/udes';
+export * from '#/boxes/altt';
 export * from '#/boxes/uncC';
 export * from '#/boxes/url';
 export * from '#/boxes/urn';
diff --git a/src/boxes/altt.ts b/src/boxes/altt.ts
new file mode 100644
index 00000000..8c301ce8
--- /dev/null
+++ b/src/boxes/altt.ts
@@ -0,0 +1,16 @@
+import { FullBox } from '#/box';
+import type { MultiBufferStream } from '#/buffer';
+
+export class alttBox extends FullBox {
+  static override readonly fourcc = 'altt' as const;
+  box_name = 'AccessibilityTextProperty' as const;
+
+  alt_text: string;
+  alt_lang: string;
+
+  parse(stream: MultiBufferStream) {
+    this.parseFullHeader(stream);
+    this.alt_text = stream.readCString();
+    this.alt_lang = stream.readCString();
+  }
+}