diff --git a/entities/src/attachment.rs b/entities/src/attachment.rs
index 541494a..48d6f4c 100644
--- a/entities/src/attachment.rs
+++ b/entities/src/attachment.rs
@@ -71,6 +71,9 @@ pub enum MediaType {
     /// A video file.
     #[serde(rename = "video")]
     Video,
+    /// An audio file.
+    #[serde(rename = "audio")]
+    Audio,
     /// A gifv format file.
     #[serde(rename = "gifv")]
     Gifv,