diff --git a/js/reading-list.js b/js/reading-list.js
index e7a94e4..7c1657f 100644
--- a/js/reading-list.js
+++ b/js/reading-list.js
@@ -64,9 +64,11 @@ function renderEntry(entry) {
   const note = entry.note
     ? `<p class="reading-note">${escapeHtml(entry.note)}</p>`
     : "";
+  // Every reading link points at an external http(s) URL (isValidUrl), so it
+  // carries rel="noopener noreferrer" as a hardening best practice.
   return (
     `<li class="reading-entry">` +
-    `<a class="reading-link" href="${escapeHtml(entry.url)}">${escapeHtml(entry.title)}</a>` +
+    `<a class="reading-link" href="${escapeHtml(entry.url)}" rel="noopener noreferrer">${escapeHtml(entry.title)}</a>` +
     note +
     `</li>`
   );
diff --git a/tests/reading-list.test.js b/tests/reading-list.test.js
index 760d685..388b98e 100644
--- a/tests/reading-list.test.js
+++ b/tests/reading-list.test.js
@@ -18,7 +18,7 @@ const indexHtml = readFileSync(join(root, "index.html"), "utf8");
 const contactHtml = readFileSync(join(root, "contact.html"), "utf8");
 const rendererSource = readFileSync(join(root, "js/reading-list.js"), "utf8");
 
-const ANCHOR_RE = /<a class="reading-link" href="([^"]*)">([^<]*)<\/a>/g;
+const ANCHOR_RE = /<a class="reading-link" href="([^"]*)"[^>]*>([^<]*)<\/a>/g;
 const ENTRY_LI_RE = /<li class="reading-entry">/g;
 const SECTION_RE = /<section class="reading-category"/g;
 
@@ -152,6 +152,14 @@ test("each rendered link has a valid href and shows its title, with the note sho
     );
   }
 
+  // All reading links point at external sites, so each carries the
+  // rel="noopener noreferrer" hardening attribute.
+  assert.equal(
+    (html.match(/rel="noopener noreferrer"/g) || []).length,
+    anchors.length,
+    "every rendered link carries rel=\"noopener noreferrer\""
+  );
+
   assert.ok(html.includes("One line of context."), "note is rendered when present");
   assert.equal(
     (html.match(/<p class="reading-note">/g) || []).length,