diff --git a/js/controller.js b/js/controller.js
index bdd9f00..b0c5b8c 100644
--- a/js/controller.js
+++ b/js/controller.js
@@ -216,6 +216,8 @@ pubsub.subscribe("MESSAGES_NEW", post => {
 	} else {
 		client.channelStore.increaseUnread(post);
 	}
+
+	client.channelStore.updateLastPostTime(post.channel_id, post["create_at"]);
 });
 
 pubsub.subscribe("CHANNEL_READ", ({endpoint, channel_id}) => {
diff --git a/js/pubsub.js b/js/pubsub.js
index 1241fee..603acf3 100644
--- a/js/pubsub.js
+++ b/js/pubsub.js
@@ -6,6 +6,7 @@ const topics = [
 	"CHANNELS_RELOADED", //
 	"CHANNEL_UPDATED", // {endpoint, channel}
 	"CHANNEL_UNREAD_UPDATED", // {endpoint, channel_id, unread, mentions}
+	"CHANNEL_LAST_POST_TIME_UPDATED", // {endpoint, channel_id, time}
 	"USERS_NEW",
 	"USERS_CHANGED",
 	"CHANNEL_MEMBERS_NEW",
diff --git a/js/store.js b/js/store.js
index 0a28b2e..49ef730 100644
--- a/js/store.js
+++ b/js/store.js
@@ -98,6 +98,18 @@ class ChannelStore {
 
 		pubsub.publish("CHANNEL_UNREAD_UPDATED", {endpoint: this.client.endpoint, channel_id, unread, mentions});
 	}
+
+	async updateLastPostTime(channel_id, time) {
+		if (this._promise === null) {
+			// Data does not exist yet and is not being requested
+			return;
+		}
+		await this._promise;
+
+		this._channels[channel_id]["last_post_at"] = time;
+
+		pubsub.publish("CHANNEL_LAST_POST_TIME_UPDATED", {endpoint: this.client.endpoint, channel_id, time});
+	}
 }
 
 
diff --git a/js/view/sidebar.js b/js/view/sidebar.js
index fea0ccc..adb18b5 100644
--- a/js/view/sidebar.js
+++ b/js/view/sidebar.js
@@ -25,8 +25,11 @@ function populateChannelList() {
 
 		let nodes = [];
 
-		for (let channel_id in channels) {
-			const channel = channels[channel_id];
+		let sortedChannels = Object.values(channels).sort((a, b) =>
+			b["last_post_at"] - a["last_post_at"]
+		);
+
+		for (const channel of sortedChannels) {
 			const team = teams[channel["team_id"]];
 
 			const chanUnread = unread[channel.id].unread;
@@ -53,7 +56,14 @@ function populateChannelList() {
 			li.dataset["id"] = channel.id;
 			li.dataset["server"] = client.endpoint;
 
-			if (chanUnread > 0) li.className = "unread";
+			const curChan = currentChannel();
+			if (curChan.endpoint === client.endpoint && curChan.channel_id === channel.id) {
+				li.className = "active";
+			}
+			if (chanUnread > 0) {
+				li.className += " unread";
+			}
+
 			nodes.push(li);
 		}
 		byId("channel_list").append(...nodes);
@@ -92,3 +102,7 @@ pubsub.subscribe("CHANNEL_UNREAD_UPDATED", ({endpoint, channel_id, unread, menti
 pubsub.subscribe("CHANNELS_RELOADED", () => {
 	populateChannelList();
 });
+
+pubsub.subscribe("CHANNEL_LAST_POST_TIME_UPDATED", () => {
+	populateChannelList();
+});