diff --git a/crates/mdbook-html/front-end/templates/toc.js.hbs b/crates/mdbook-html/front-end/templates/toc.js.hbs
index ec77e4c0..4d0306a6 100644
--- a/crates/mdbook-html/front-end/templates/toc.js.hbs
+++ b/crates/mdbook-html/front-end/templates/toc.js.hbs
@@ -327,6 +327,16 @@ window.customElements.define('mdbook-sidebar-scrollbox', MDBookSidebarScrollbox)
         });
     }
 
+    // Takes the nodes from the given head and copies them over to the
+    // destination, along with some filtering.
+    function filterHeader(source, dest) {
+        const clone = source.cloneNode(true);
+        clone.querySelectorAll('mark').forEach(mark => {
+            mark.replaceWith(...mark.childNodes);
+        });
+        dest.append(...clone.childNodes);
+    }
+
     // Scans page for headers and adds them to the sidebar.
     document.addEventListener('DOMContentLoaded', function() {
         const activeSection = document.querySelector('#mdbook-sidebar .active');
@@ -399,7 +409,7 @@ window.customElements.define('mdbook-sidebar-scrollbox', MDBookSidebarScrollbox)
             span.appendChild(a);
             a.href = '#' + header.id;
             a.classList.add('header-in-summary');
-            a.innerHTML = header.children[0].innerHTML;
+            filterHeader(header.children[0], a);
             a.addEventListener('click', headerThresholdClick);
             const nextHeader = headers[i + 1];
             if (nextHeader !== undefined) {
diff --git a/tests/gui/heading-nav-filter.goml b/tests/gui/heading-nav-filter.goml
index 7299833f..a42892db 100644
--- a/tests/gui/heading-nav-filter.goml
+++ b/tests/gui/heading-nav-filter.goml
@@ -5,4 +5,4 @@ go-to: |DOC_PATH| + "heading-nav/filtered-headings.html?highlight=skateboard#ska
 
 assert-property: ("//h2[@id='skateboard']", {"innerHTML": '<a class="header" href="#skateboard"><mark data-markjs="true">Skateboard</mark></a>'})
 
-assert-property: ("//a[contains(@class, 'header-in-summary') and @href='#skateboard']", {"innerHTML": '<mark data-markjs="true">Skateboard</mark>'})
+assert-property: ("//a[contains(@class, 'header-in-summary') and @href='#skateboard']", {"innerHTML": 'Skateboard'})