diff --git a/tests/e2e/markdown-editor.test.e2e.ts b/tests/e2e/markdown-editor.test.e2e.ts
index 3f6e1608b6..e2c2f36ed1 100644
--- a/tests/e2e/markdown-editor.test.e2e.ts
+++ b/tests/e2e/markdown-editor.test.e2e.ts
@@ -560,3 +560,29 @@ test('Markdown bold/italic toolbar and shortcut', async ({page}) => {
   await textarea.press('ControlOrMeta+KeyI');
   await expect(textarea).toHaveValue(`line 1\nline 2\nline 3\nline 4`);
 });
+
+test('Monospace button aria-label', async ({page}) => {
+  // Load page with editor
+  const response = await page.goto('/user2/repo1/issues/new');
+  expect(response?.status()).toBe(200);
+
+  const monospaceButton = page.locator('.markdown-switch-monospace');
+  const enableText = await monospaceButton.getAttribute('data-enable-text');
+  const disableText = await monospaceButton.getAttribute('data-disable-text');
+
+  async function assertAriaLabel(enabled: boolean) {
+    const expected = enabled ? disableText : enableText;
+
+    await expect(monospaceButton).toHaveAttribute('aria-label', expected);
+  }
+
+  const enabled = await monospaceButton.getAttribute('aria-checked') === 'true';
+
+  await assertAriaLabel(enabled);
+
+  await monospaceButton.click();
+  await assertAriaLabel(!enabled);
+
+  await monospaceButton.click();
+  await assertAriaLabel(enabled);
+});
diff --git a/web_src/js/features/comp/ComboMarkdownEditor.js b/web_src/js/features/comp/ComboMarkdownEditor.js
index 8c010ae386..b4bc443c0e 100644
--- a/web_src/js/features/comp/ComboMarkdownEditor.js
+++ b/web_src/js/features/comp/ComboMarkdownEditor.js
@@ -176,6 +176,7 @@ class ComboMarkdownEditor {
     const monospaceEnabled = localStorage?.getItem('markdown-editor-monospace') === 'true';
     const monospaceText = monospaceButton.getAttribute(monospaceEnabled ? 'data-disable-text' : 'data-enable-text');
     monospaceButton.setAttribute('data-tooltip-content', monospaceText);
+    monospaceButton.setAttribute('aria-label', monospaceText);
     monospaceButton.setAttribute('aria-checked', String(monospaceEnabled));
 
     monospaceButton?.addEventListener('click', (e) => {
@@ -185,6 +186,7 @@ class ComboMarkdownEditor {
       this.textarea.classList.toggle('tw-font-mono', enabled);
       const text = monospaceButton.getAttribute(enabled ? 'data-disable-text' : 'data-enable-text');
       monospaceButton.setAttribute('data-tooltip-content', text);
+      monospaceButton.setAttribute('aria-label', text);
       monospaceButton.setAttribute('aria-checked', String(enabled));
     });