diff --git a/tests/mocha/index.html b/tests/mocha/index.html
index d4d40331441..694d5215aac 100644
--- a/tests/mocha/index.html
+++ b/tests/mocha/index.html
@@ -18,9 +18,9 @@
     }
   </style>
   <body>
-
     <div id="mocha"></div>
     <div id="failureCount" style="display:none" tests_failed="unset"></div>
+    <div id="failureMessages" style="display:none"></div>
     <script src="../../node_modules/chai/chai.js"></script>
     <script src="../../node_modules/mocha/mocha.js"></script>
     <script src="../../node_modules/sinon/pkg/sinon.js"></script>
@@ -173,10 +173,16 @@
     </xml>
 
     <script type="module">
-      mocha.run(function(failures) {
+      let runner = mocha.run(function(failures) {
         var failureDiv = document.getElementById('failureCount');
         failureDiv.setAttribute('tests_failed', failures);
       });
+      runner.on('fail', function(test, err) {
+        const msg = document.createElement('p');
+        msg.textContent = `"${test.fullTitle()}" failed: ${err.message}`;
+        const div = document.getElementById('failureMessages');
+        div.appendChild(msg);
+      });
     </script>
   </body>
 </html>
diff --git a/tests/mocha/run_mocha_tests_in_browser.js b/tests/mocha/run_mocha_tests_in_browser.js
index d4dc83fbe5e..217c9992bc6 100644
--- a/tests/mocha/run_mocha_tests_in_browser.js
+++ b/tests/mocha/run_mocha_tests_in_browser.js
@@ -61,8 +61,18 @@ async function runMochaTestsInBrowser() {
   const elem = await browser.$('#failureCount');
   const numOfFailure = await elem.getAttribute('tests_failed');
 
+  if (numOfFailure > 0) {
+    console.log('============Blockly Mocha Test Failures================')
+    const failureMessagesEls = await browser.$$('#failureMessages p');
+    if (!failureMessagesEls.length) {
+      console.log('There is at least one test failure, but no messages reported. Mocha may be failing because no tests are being run.');
+    }
+    for (let el of failureMessagesEls) {
+      console.log(await el.getText());
+    }
+  }
+
   console.log('============Blockly Mocha Test Summary=================');
-  console.log(numOfFailure);
   console.log(numOfFailure + ' tests failed');
   console.log('============Blockly Mocha Test Summary=================');
   if (parseInt(numOfFailure) !== 0) {
