diff --git a/html/webappapis/dynamic-markup-insertion/html-unsafe-methods/setHTMLUnsafe-xml.html b/html/webappapis/dynamic-markup-insertion/html-unsafe-methods/setHTMLUnsafe-xml.html
new file mode 100644
index 00000000000000..d7211e97f1e2ea
--- /dev/null
+++ b/html/webappapis/dynamic-markup-insertion/html-unsafe-methods/setHTMLUnsafe-xml.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<link rel=author href="mailto:jarhar@chromium.org">
+<link rel=help href="https://github.com/whatwg/html/pull/9538">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+test(() => {
+  const xmlDoc = document.implementation.createDocument(null, 'root', null);
+  assert_equals(xmlDoc.contentType, 'application/xml');
+  // Intentionally unclosed and misnested tags
+  xmlDoc.documentElement.setHTMLUnsafe('<p><foo><b><i>test</b></i>');
+  assert_equals(xmlDoc.documentElement.innerHTML,
+    '<p xmlns="http://www.w3.org/1999/xhtml"><foo><b><i>test</i></b></foo></p>',
+    'Element.setHTMLUnsafe should use the HTML parser in XML documents.');
+}, 'setHTMLUnsafe should still parse HTML even in XML documents.');
+
+test(() => {
+  const svgDoc = document.implementation.createDocument('http://www.w3.org/2000/svg', 'root', null);
+  assert_equals(svgDoc.contentType, 'image/svg+xml');
+  // Intentionally unclosed and misnested tags
+  svgDoc.documentElement.setHTMLUnsafe('<p><foo><b><i>test</b></i>');
+  assert_equals(svgDoc.documentElement.innerHTML,
+    '<p xmlns="http://www.w3.org/1999/xhtml"><foo><b><i>test</i></b></foo></p>',
+    'Element.setHTMLUnsafe should use the HTML parser in SVG documents.');
+}, 'setHTMLUnsafe should still parse HTML even in SVG documents.');
+</script>
