diff --git a/src/Unread.js b/src/Unread.js
index 67166dc24f..8a70291cf2 100644
--- a/src/Unread.js
+++ b/src/Unread.js
@@ -37,7 +37,26 @@ module.exports = {
     },
 
     doesRoomHaveUnreadMessages: function(room) {
-        var readUpToId = room.getEventReadUpTo(MatrixClientPeg.get().credentials.userId);
+        var myUserId = MatrixClientPeg.get().credentials.userId;
+
+        // get the most recent read receipt sent by our account.
+        // N.B. this is NOT a read marker (RM, aka "read up to marker"),
+        // despite the name of the method :((
+        var readUpToId = room.getEventReadUpTo(myUserId);
+
+        // as we don't send RRs for our own messages, make sure we special case that
+        // if *we* sent the last message into the room, we consider it not unread!
+        // Should fix: https://github.com/vector-im/riot-web/issues/3263
+        //             https://github.com/vector-im/riot-web/issues/2427
+        // ...and possibly some of the others at
+        //             https://github.com/vector-im/riot-web/issues/3363
+        if (room.timeline.length &&
+            room.timeline[room.timeline.length - 1].sender &&
+            room.timeline[room.timeline.length - 1].sender.userId === myUserId)
+        {
+            return false;
+        }
+
         // this just looks at whatever history we have, which if we've only just started
         // up probably won't be very much, so if the last couple of events are ones that
         // don't count, we don't know if there are any events that do count between where