diff --git a/src/domain/session/room/timeline/ReactionsViewModel.js b/src/domain/session/room/timeline/ReactionsViewModel.js
new file mode 100644
index 00000000..cdb98dcd
--- /dev/null
+++ b/src/domain/session/room/timeline/ReactionsViewModel.js
@@ -0,0 +1,92 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import {ViewModel} from "../../../ViewModel.js";
+import {ObservableMap} from "../../../../observable/map/ObservableMap.js";
+
+export class ReactionsViewModel extends ViewModel {
+    constructor(parentEntry) {
+        super();
+        this._parentEntry = parentEntry;
+        this._map = new ObservableMap();
+        this._reactions = this._map.sortValues((a, b) => a._compare(b));
+    }
+
+    update(annotations) {
+        for (const key in annotations) {
+            if (annotations.hasOwnProperty(key)) {
+                const annotation = annotations[key];
+                const reaction = this._map.get(key);
+                if (reaction) {
+                    if (reaction._tryUpdate(annotation)) {
+                        this._map.update(key);
+                    }
+                } else {
+                    this._map.add(key, new ReactionViewModel(key, annotation, this._parentEntry));
+                }
+            }
+        }
+        for (const existingKey of this._map.keys()) {
+            if (!annotations.hasOwnProperty(existingKey)) {
+                this._map.remove(existingKey);
+            }
+        }
+    }
+
+    get reactions() {
+        return this._reactions;
+    }
+}
+
+class ReactionViewModel extends ViewModel {
+    constructor(key, annotation, parentEntry) {
+        super();
+        this._key = key;
+        this._annotation = annotation;
+        this._parentEntry = parentEntry;
+    }
+
+    _tryUpdate(annotation) {
+        if (
+            annotation.me !== this._annotation.me ||
+            annotation.count !== this._annotation.count ||
+            annotation.firstTimestamp !== this._annotation.firstTimestamp
+        ) {
+            this._annotation = annotation;
+            return true;
+        }
+        return false;
+    }
+
+    get key() {
+        return this._key;
+    }
+
+    get count() {
+        return this._annotation.count;
+    }
+
+    get haveReacted() {
+        return this._annotation.me;
+    }
+
+    _compare(other) {
+        return this._annotation.count - other._annotation.count;
+    }
+
+    react() {
+        return this._parentEntry.react(this.key);
+    }
+}
\ No newline at end of file
diff --git a/src/domain/session/room/timeline/tiles/BaseMessageTile.js b/src/domain/session/room/timeline/tiles/BaseMessageTile.js
index 704cccb8..b03e2fee 100644
--- a/src/domain/session/room/timeline/tiles/BaseMessageTile.js
+++ b/src/domain/session/room/timeline/tiles/BaseMessageTile.js
@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import {SimpleTile} from "./SimpleTile.js";
+import {ReactionsViewModel} from "../ReactionsViewModel.js";
 import {getIdentifierColorNumber, avatarInitials, getAvatarHttpUrl} from "../../../../avatar.js";
 
 export class BaseMessageTile extends SimpleTile {
@@ -22,6 +23,10 @@ export class BaseMessageTile extends SimpleTile {
         super(options);
         this._date = this._entry.timestamp ? new Date(this._entry.timestamp) : null;
         this._isContinuation = false;
+        this._reactions = null;
+        if (this._entry.annotations) {
+            this._updateReactions();
+        }
     }
 
     get _room() {
@@ -97,6 +102,14 @@ export class BaseMessageTile extends SimpleTile {
         }
     }
 
+    updateEntry(entry, param) {
+        const action = super.updateEntry(entry, param);
+        if (action.shouldUpdate) {
+            this._updateReactions();
+        }
+        return action;
+    }
+
     redact(reason, log) {
         return this._room.sendRedaction(this._entry.id, reason, log);
     }
@@ -104,4 +117,29 @@ export class BaseMessageTile extends SimpleTile {
     get canRedact() {
         return this._powerLevels.canRedactFromSender(this._entry.sender);
     }
+
+    get reactions() {
+        return this._reactions;
+    }
+
+    _updateReactions() {
+        const {annotations} = this._entry;
+        if (!annotations) {
+            if (this._reactions) {
+                this._reactions = null;
+                this.emitChange("reactions");
+            }
+        }
+        let isNewMap = false;
+        if (!this._reactions) {
+            this._reactions = new ReactionsViewModel(this);
+            isNewMap = true;
+        }
+
+        this._reactions.update(annotations);
+
+        if (isNewMap) {
+            this.emitChange("reactions");
+        }
+    }
 }
diff --git a/src/matrix/room/timeline/entries/EventEntry.js b/src/matrix/room/timeline/entries/EventEntry.js
index b19415c5..8f532f02 100644
--- a/src/matrix/room/timeline/entries/EventEntry.js
+++ b/src/matrix/room/timeline/entries/EventEntry.js
@@ -126,4 +126,8 @@ export class EventEntry extends BaseEventEntry {
         // fall back to local echo reason
         return super.redactionReason;
     }
+
+    get annotations() {
+        return this._eventEntry.annotations;
+    }
 }
\ No newline at end of file
diff --git a/src/observable/map/ObservableMap.js b/src/observable/map/ObservableMap.js
index 7fe10d95..4e9df5bb 100644
--- a/src/observable/map/ObservableMap.js
+++ b/src/observable/map/ObservableMap.js
@@ -74,6 +74,10 @@ export class ObservableMap extends BaseObservableMap {
     values() {
         return this._values.values();
     }
+
+    keys() {
+        return this._values.keys();
+    }
 }
 
 export function tests() {