diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 4bbd447339f..d12214eb9c9 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -39677,6 +39677,12 @@
     "deleted_reftests": {},
     "items": {
       "testharness": {
+        "css-values/unset-value-storage.html": [
+          {
+            "path": "css-values/unset-value-storage.html",
+            "url": "/css-values/unset-value-storage.html"
+          }
+        ],
         "cssom/CSSKeyframesRule.html": [
           {
             "path": "cssom/CSSKeyframesRule.html",
diff --git a/tests/wpt/web-platform-tests/css-values/unset-value-storage.html b/tests/wpt/web-platform-tests/css-values/unset-value-storage.html
new file mode 100644
index 00000000000..9cf13b250d8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css-values/unset-value-storage.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Storage of "unset" value</title>
+<meta name="author" title="Xidorn Quan" href="https://www.upsuper.org">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  div {
+    color: unset;
+    border: unset;
+  }
+</style>
+<body>
+  <div id="log"></div>
+  <script>
+    test(function() {
+      let properties = ["color", "border", "border-left", "border-color", "border-right-style"];
+      let style = document.styleSheets[0].cssRules[0].style;
+      for (let prop of properties) {
+        assert_equals(style.getPropertyValue(prop), "unset", `${prop} is expected to be "unset"`);
+      }
+    });
+  </script>
