diff --git a/crates/ruma-common/src/events/sticker.rs b/crates/ruma-common/src/events/sticker.rs
index 2ff18406..a79ab4f4 100644
--- a/crates/ruma-common/src/events/sticker.rs
+++ b/crates/ruma-common/src/events/sticker.rs
@@ -5,6 +5,12 @@
 use ruma_macros::EventContent;
 use serde::{Deserialize, Serialize};
 
+#[cfg(feature = "unstable-msc3552")]
+use super::{
+    file::FileContent,
+    image::{ImageContent, ThumbnailContent},
+    message::MessageContent,
+};
 use crate::{events::room::ImageInfo, MxcUri};
 
 /// The content of an `m.sticker` event.
@@ -25,11 +31,80 @@ pub struct StickerEventContent {
 
     /// The URL to the sticker image.
     pub url: Box<MxcUri>,
+
+    /// Extensible-event text representation of the message.
+    ///
+    /// If present, this should be preferred over the `body` field.
+    #[cfg(feature = "unstable-msc3552")]
+    #[serde(flatten, skip_serializing_if = "Option::is_none")]
+    pub message: Option<MessageContent>,
+
+    /// Extensible-event file content of the message.
+    ///
+    /// If present, this should be preferred over the `url`, `file` and `info` fields.
+    #[cfg(feature = "unstable-msc3552")]
+    #[serde(
+        rename = "org.matrix.msc1767.file",
+        alias = "m.file",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub file: Option<FileContent>,
+
+    /// Extensible-event image info of the message.
+    ///
+    /// If present, this should be preferred over the `info` field.
+    #[cfg(feature = "unstable-msc3552")]
+    #[serde(
+        rename = "org.matrix.msc1767.image",
+        alias = "m.image",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub image: Option<Box<ImageContent>>,
+
+    /// Extensible-event thumbnails of the message.
+    ///
+    /// If present, this should be preferred over the `info` field.
+    #[cfg(feature = "unstable-msc3552")]
+    #[serde(
+        rename = "org.matrix.msc1767.thumbnail",
+        alias = "m.thumbnail",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub thumbnail: Option<Vec<ThumbnailContent>>,
+
+    /// Extensible-event captions of the message.
+    #[cfg(feature = "unstable-msc3552")]
+    #[serde(
+        rename = "org.matrix.msc1767.caption",
+        alias = "m.caption",
+        with = "super::message::content_serde::as_vec",
+        default,
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub caption: Option<MessageContent>,
 }
 
 impl StickerEventContent {
     /// Creates a new `StickerEventContent` with the given body, image info and URL.
     pub fn new(body: String, info: ImageInfo, url: Box<MxcUri>) -> Self {
-        Self { body, info, url }
+        Self {
+            #[cfg(feature = "unstable-msc3552")]
+            message: Some(MessageContent::plain(body.clone())),
+            #[cfg(feature = "unstable-msc3552")]
+            file: Some(FileContent::plain(url.clone(), Some(Box::new((&info).into())))),
+            #[cfg(feature = "unstable-msc3552")]
+            image: Some(Box::new((&info).into())),
+            #[cfg(feature = "unstable-msc3552")]
+            thumbnail: ThumbnailContent::from_room_message_content(
+                info.thumbnail_source.as_ref(),
+                info.thumbnail_info.as_deref(),
+            )
+            .map(|thumbnail| vec![thumbnail]),
+            #[cfg(feature = "unstable-msc3552")]
+            caption: None,
+            body,
+            info,
+            url,
+        }
     }
 }
diff --git a/crates/ruma-common/tests/events/message_event.rs b/crates/ruma-common/tests/events/message_event.rs
index 38ef9db9..fb9348a3 100644
--- a/crates/ruma-common/tests/events/message_event.rs
+++ b/crates/ruma-common/tests/events/message_event.rs
@@ -44,6 +44,8 @@ fn message_serialize_sticker() {
     };
 
     let actual = to_json_value(&aliases_event).unwrap();
+
+    #[cfg(not(feature = "unstable-msc3552"))]
     let expected = json!({
         "content": {
             "body": "Hello",
@@ -69,6 +71,51 @@ fn message_serialize_sticker() {
         "type": "m.sticker",
     });
 
+    #[cfg(feature = "unstable-msc3552")]
+    let expected = json!({
+        "content": {
+            "body": "Hello",
+            "info": {
+                "h": 423,
+                "mimetype": "image/png",
+                "size": 84242,
+                "thumbnail_info": {
+                  "h": 334,
+                  "mimetype": "image/png",
+                  "size": 82595,
+                  "w": 800
+                },
+                "thumbnail_url": "mxc://matrix.org/irsns989Rrsn",
+                "w": 1011
+              },
+            "url": "mxc://matrix.org/rnsldl8srs98IRrs",
+            "org.matrix.msc1767.text": "Hello",
+            "org.matrix.msc1767.file": {
+                "url": "mxc://matrix.org/rnsldl8srs98IRrs",
+                "mimetype": "image/png",
+                "size": 84242,
+            },
+            "org.matrix.msc1767.image": {
+                "height": 423,
+                "width": 1011,
+            },
+            "org.matrix.msc1767.thumbnail": [
+                {
+                    "url": "mxc://matrix.org/irsns989Rrsn",
+                    "mimetype": "image/png",
+                    "size": 82595,
+                    "height": 334,
+                    "width": 800,
+                }
+            ],
+        },
+        "event_id": "$h29iv0s8:example.com",
+        "origin_server_ts": 1,
+        "room_id": "!roomid:room.com",
+        "sender": "@carl:example.com",
+        "type": "m.sticker",
+    });
+
     assert_eq!(actual, expected);
 }
 
diff --git a/crates/ruma-common/tests/events/mod.rs b/crates/ruma-common/tests/events/mod.rs
index dc500bae..c078e4aa 100644
--- a/crates/ruma-common/tests/events/mod.rs
+++ b/crates/ruma-common/tests/events/mod.rs
@@ -19,6 +19,7 @@ mod redaction;
 mod relations;
 mod room_message;
 mod state_event;
+mod sticker;
 mod stripped;
 mod to_device;
 mod video;
diff --git a/crates/ruma-common/tests/events/sticker.rs b/crates/ruma-common/tests/events/sticker.rs
new file mode 100644
index 00000000..531f127c
--- /dev/null
+++ b/crates/ruma-common/tests/events/sticker.rs
@@ -0,0 +1,78 @@
+#![cfg(feature = "unstable-msc3552")]
+
+use ruma_common::{
+    events::{room::ImageInfo, sticker::StickerEventContent},
+    mxc_uri,
+};
+use serde_json::{from_value as from_json_value, json, to_value as to_json_value};
+
+#[test]
+fn content_serialization() {
+    let message_event_content = StickerEventContent::new(
+        "Upload: my_image.jpg".to_owned(),
+        ImageInfo::new(),
+        mxc_uri!("mxc://notareal.hs/file").to_owned(),
+    );
+
+    assert_eq!(
+        to_json_value(&message_event_content).unwrap(),
+        json!({
+            "body": "Upload: my_image.jpg",
+            "url": "mxc://notareal.hs/file",
+            "info": {},
+            "org.matrix.msc1767.text": "Upload: my_image.jpg",
+            "org.matrix.msc1767.file": {
+                "url": "mxc://notareal.hs/file",
+            },
+            "org.matrix.msc1767.image": {},
+        })
+    );
+}
+
+#[test]
+fn content_stable_deserialization() {
+    let json_data = json!({
+        "body": "Upload: my_image.jpg",
+        "url": "mxc://notareal.hs/file",
+        "info": {},
+        "m.text": "Upload: my_image.jpg",
+        "m.file": {
+            "url": "mxc://notareal.hs/file",
+        },
+        "m.image": {},
+    });
+
+    let content = from_json_value::<StickerEventContent>(json_data).unwrap();
+    assert_eq!(content.body, "Upload: my_image.jpg");
+    assert_eq!(content.url, "mxc://notareal.hs/file");
+    let message = content.message.unwrap();
+    assert_eq!(message.len(), 1);
+    assert_eq!(message[0].body, "Upload: my_image.jpg");
+    let file = content.file.unwrap();
+    assert_eq!(file.url, "mxc://notareal.hs/file");
+    assert!(!file.is_encrypted());
+}
+
+#[test]
+fn content_unstable_deserialization() {
+    let json_data = json!({
+        "body": "Upload: my_image.jpg",
+        "url": "mxc://notareal.hs/file",
+        "info": {},
+        "org.matrix.msc1767.text": "Upload: my_image.jpg",
+        "org.matrix.msc1767.file": {
+            "url": "mxc://notareal.hs/file",
+        },
+        "org.matrix.msc1767.image": {},
+    });
+
+    let content = from_json_value::<StickerEventContent>(json_data).unwrap();
+    assert_eq!(content.body, "Upload: my_image.jpg");
+    assert_eq!(content.url, "mxc://notareal.hs/file");
+    let message = content.message.unwrap();
+    assert_eq!(message.len(), 1);
+    assert_eq!(message[0].body, "Upload: my_image.jpg");
+    let file = content.file.unwrap();
+    assert_eq!(file.url, "mxc://notareal.hs/file");
+    assert!(!file.is_encrypted());
+}