diff --git a/testing/web-platform/tests/intersection-observer/v2/drop-shadow-filter-vertical-rl.html b/testing/web-platform/tests/intersection-observer/v2/drop-shadow-filter-vertical-rl.html
new file mode 100644
index 000000000000..fc5b145e1fb4
--- /dev/null
+++ b/testing/web-platform/tests/intersection-observer/v2/drop-shadow-filter-vertical-rl.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/intersection-observer-test-utils.js"></script>
+
+<style>
+body, html {
+  margin: 0;
+}
+pre, #log {
+  position: absolute;
+  top: 150px;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background-color: green;
+  float: left;
+}
+#occluder {
+  float: left;
+  margin-left: 10px;
+  width: 100px;
+  height: 100px;
+  background-color: blue;
+  filter: drop-shadow(-50px 0);
+  writing-mode: vertical-rl;
+}
+</style>
+
+<div id="target"></div>
+<div id="occluder"></div>
+
+<script>
+var delay = 100;
+var entries = [];
+var target;
+var occluder;
+
+runTestCycle(function() {
+  target = document.getElementById("target");
+  occluder = document.getElementById("occluder");
+  assert_true(!!target, "target exists");
+  assert_true(!!occluder, "occluder exists");
+  var observer = new IntersectionObserver(function(changes) {
+    entries = entries.concat(changes)
+  }, {trackVisibility: true, delay: delay});
+  observer.observe(target);
+  entries = entries.concat(observer.takeRecords());
+  assert_equals(entries.length, 0, "No initial notifications.");
+  runTestCycle(step0, "First rAF.", delay);
+}, "IntersectionObserverV2 in a single document using the implicit root, with an occluding element.", delay);
+
+function step0() {
+  // Occluding elements with opacity=0 should not affect target visibility.
+  occluder.style.opacity = "0";
+  runTestCycle(step2, "occluder.style.opacity = 0", delay);
+
+  // First notification should report occlusion due to drop shadow filter.
+  checkLastEntry(entries, 0, [0, 100, 0, 100, 0, 100, 0, 100, 0, 800, 0, 600, true, false]);
+}
+
+function step2() {
+  checkLastEntry(entries, 1, [0, 100, 0, 100, 0, 100, 0, 100, 0, 800, 0, 600, true, true]);
+}
+</script>
