diff --git a/CHANGELOG.md b/CHANGELOG.md
index 227e2d3..de109a0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ This website is built from the `HEAD` of the `main` branch of the theme reposito
 
 Code changes to `main` that are *not* in the latest release:
 
+- Fixed: incorrect navigation when `.html` omitted from URL by [@pdmosses] in [#1374]
 - Fixed: incorrect positioning of clickable area for navigation links on Safari by [@mattxwang] in [#1403]
 
 Docs changes made since the latest release:
@@ -29,6 +30,7 @@ Docs changes made since the latest release:
 
 [@mitchnemirov]: https://github.com/mitchnemirov
 
+[#1374]: https://github.com/just-the-docs/just-the-docs/pull/1374
 [#1390]: https://github.com/just-the-docs/just-the-docs/pull/1390
 [#1403]: https://github.com/just-the-docs/just-the-docs/pull/1403
 
diff --git a/assets/js/just-the-docs.js b/assets/js/just-the-docs.js
index 4f0296d..bf3755f 100644
--- a/assets/js/just-the-docs.js
+++ b/assets/js/just-the-docs.js
@@ -487,11 +487,28 @@ jtd.setTheme = function(theme) {
 // and not have the slash on GitHub Pages
 
 function navLink() {
-  var href = document.location.pathname;
-  if (href.endsWith('/') && href != '/') {
-    href = href.slice(0, -1);
+  var pathname = document.location.pathname;
+  
+  var navLink = document.getElementById('site-nav').querySelector('a[href="' + pathname + '"]');
+  if (navLink) {
+    return navLink;
   }
-  return document.getElementById('site-nav').querySelector('a[href="' + href + '"], a[href="' + href + '/"]');
+
+  // The `permalink` setting may produce navigation links whose `href` ends with `/` or `.html`.
+  // To find these links when `/` is omitted from or added to pathname, or `.html` is omitted:
+
+  if (pathname.endsWith('/') && pathname != '/') {
+    pathname = pathname.slice(0, -1);
+  }
+
+  if (pathname != '/') {
+    navLink = document.getElementById('site-nav').querySelector('a[href="' + pathname + '"], a[href="' + pathname + '/"], a[href="' + pathname + '.html"]');
+    if (navLink) {
+      return navLink;
+    }
+  }
+
+  return null; // avoids `undefined`
 }
 
 // Scroll site-nav to ensure the link to the current page is visible