diff --git a/frontend_tests/node_tests/alert_words.js b/frontend_tests/node_tests/alert_words.js
index 341c11ad8d..08f4324d6e 100644
--- a/frontend_tests/node_tests/alert_words.js
+++ b/frontend_tests/node_tests/alert_words.js
@@ -3,7 +3,7 @@ add_dependencies({
 });
 
 set_global('page_params', {
-    alert_words: ['alertone', 'alerttwo', 'alertthree', 'al*rt.*s', '.+'],
+    alert_words: ['alertone', 'alerttwo', 'alertthree', 'al*rt.*s', '.+', 'emoji'],
 });
 
 set_global('feature_flags', {
@@ -41,7 +41,9 @@ var question_word_message = { sender_email: 'another@zulip.com', content: '<p>st
 
 var alert_domain_message = { sender_email: 'another@zulip.com', content: '<p>now with link <a href="http://www.alerttwo.us/foo/bar" target="_blank" title="http://www.alerttwo.us/foo/bar">www.alerttwo.us/foo/bar</a></p>',
                      alerted: true };
-
+// This test ensure we are not mucking up rendered HTML content.
+var message_with_emoji = { sender_email: 'another@zulip.com', content: '<p>I <img alt=":heart:" class="emoji" src="/static/generated/emoji/images/emoji/unicode/2764.png" title="heart"> emoji!</p>',
+                           alerted: true };
 
 (function test_notifications() {
     assert(!alert_words.notifies(regular_message));
@@ -52,6 +54,7 @@ var alert_domain_message = { sender_email: 'another@zulip.com', content: '<p>now
     assert(alert_words.notifies(multialert_message));
     assert(alert_words.notifies(unsafe_word_message));
     assert(alert_words.notifies(alert_domain_message));
+    assert(alert_words.notifies(message_with_emoji));
 }());
 
 (function test_munging() {
@@ -82,4 +85,7 @@ var alert_domain_message = { sender_email: 'another@zulip.com', content: '<p>now
 
     alert_words.process_message(alert_domain_message);
     assert.equal(alert_domain_message.content, '<p>now with link <a href="http://www.alerttwo.us/foo/bar" target="_blank" title="http://www.alerttwo.us/foo/bar">www.<span class=\'alert-word\'>alerttwo</span>.us/foo/bar</a></p>');
+
+    alert_words.process_message(message_with_emoji);
+    assert.equal(message_with_emoji.content, '<p>I <img alt=":heart:" class="emoji" src="/static/generated/emoji/images/emoji/unicode/2764.png" title="heart"> <span class=\'alert-word\'>emoji</span>!</p>');
 }());
diff --git a/static/js/alert_words.js b/static/js/alert_words.js
index fb0bdc0dbb..fed423e0f4 100644
--- a/static/js/alert_words.js
+++ b/static/js/alert_words.js
@@ -13,9 +13,6 @@ function escape_user_regex(value) {
     return value.replace(/[\-\[\]{}()*+?.,\\\^$|#\s]/g, "\\$&");
 }
 
-var find_href_backwards = /href=['"][\w:\/\.]+$/;
-var find_title_backwards = /title=['"][\w:\/\.]+$/;
-
 exports.process_message = function (message) {
     if (!exports.notifies(message)) {
         return;
@@ -32,9 +29,16 @@ exports.process_message = function (message) {
                                '(' + after_punctuation + ')' , 'ig');
         message.content = message.content.replace(regex, function (match, before, word,
                                                                    after, offset, content) {
-            // Don't munge URL hrefs
+            // Logic for ensuring that we don't muck up rendered HTML.
             var pre_match = content.substring(0, offset);
-            if (find_href_backwards.exec(pre_match) || find_title_backwards.exec(pre_match)) {
+            // We want to find the position of the `<` and `>` only in the
+            // match and the string before it. So, don't include the last
+            // character of match in `check_string`. This covers the corner
+            // case when there is an alert word just before `<` or `>`.
+            var check_string = pre_match + match.substring(0, match.length - 1);
+            var in_tag = check_string.lastIndexOf('<') > check_string.lastIndexOf('>');
+            // Matched word is inside a HTML tag so don't perform any highlighting.
+            if (in_tag === true) {
                 return before + word + after;
             }
             return before + "<span class='alert-word'>" + word + "</span>" + after;