diff --git a/src/core/dfn-index.js b/src/core/dfn-index.js
index 3bfa9772e1..83f831cfd6 100644
--- a/src/core/dfn-index.js
+++ b/src/core/dfn-index.js
@@ -45,6 +45,13 @@ const localizationStrings = {
     dfnOf: "definición de",
     definesFollowing: "define lo siguiente:",
   },
+  fr: {
+    heading: "Index",
+    headingExternal: "Termes définis par référence",
+    headingLocal: "Termes définis par cette spécification",
+    dfnOf: "définition de",
+    definesFollowing: "définit les termes suivants :",
+  },
   ja: {
     heading: "索引",
     headingExternal: "参照によって定義された用語",
@@ -344,6 +351,9 @@ function collectExternalTerms() {
     if (!elem.dataset.cite) {
       continue;
     }
+    if ("noindex" in elem.dataset) {
+      continue;
+    }
     const { cite, citeFrag, xrefType, linkType } = elem.dataset;
     if (!(xrefType || linkType || cite.includes("#") || citeFrag)) {
       // Not a reference to a definition
@@ -459,4 +469,8 @@ function cleanup(doc) {
   doc
     .querySelectorAll("#index-defined-here li[data-id]")
     .forEach(el => el.removeAttribute("data-id"));
+
+  doc
+    .querySelectorAll("a[data-noindex]")
+    .forEach(el => el.removeAttribute("data-noindex"));
 }
diff --git a/tests/spec/core/dfn-index-spec.js b/tests/spec/core/dfn-index-spec.js
index c562565c83..1739801be6 100644
--- a/tests/spec/core/dfn-index-spec.js
+++ b/tests/spec/core/dfn-index-spec.js
@@ -502,5 +502,24 @@ describe("Core — dfn-index", () => {
       expect(parsing1.id).toBe("index-term-parsing");
       expect(parsing2.id).toBe("index-term-parsing-0");
     });
+
+    it("excludes terms with data-noindex from the external index", async () => {
+      const body = `<section data-cite="DOM">
+          <h2>TEST</h2>
+          <p>{{ Event }} {{ Event/type }}</p>
+          <p><a data-cite="DOM#interface-event" data-noindex>Event (noindex)</a></p>
+        </section>
+        <section id="index"></section>`;
+      const ops = makeStandardOps({ xref: "web-platform" }, body);
+      const doc = await makeRSDoc(ops);
+      const externalIndex = doc.getElementById("index-defined-elsewhere");
+      expect(externalIndex).toBeTruthy();
+      const terms = [...externalIndex.querySelectorAll(".index-term")].map(el =>
+        el.textContent.trim()
+      );
+      expect(terms.length).toBeGreaterThan(0);
+      expect(terms).toContain("Event interface");
+      expect(terms).not.toContain("Event (noindex)");
+    });
   });
 });