diff --git a/testing/web-platform/tests/fledge/tentative/score-ad-browser-signals.https.window.js b/testing/web-platform/tests/fledge/tentative/score-ad-browser-signals.https.window.js
new file mode 100644
index 0000000000000..f20412cfc7857
--- /dev/null
+++ b/testing/web-platform/tests/fledge/tentative/score-ad-browser-signals.https.window.js
@@ -0,0 +1,57 @@
+// META: script=/resources/testdriver.js
+// META: script=/common/utils.js
+// META: script=resources/fledge-util.sub.js
+// META: script=/common/subset-tests.js
+// META: timeout=long
+
+"use strict;"
+
+// These tests focus on the browserSignals argument passed to scoreAd().
+
+subsetTest(promise_test, async test => {
+  const uuid = generateUuid(test);
+
+  let biddingLogicURL = createBiddingScriptURL(
+    {
+      generateBid:
+        `
+          return {
+            bid: 1,
+            render: { url: interestGroup.ads[0].renderURL,
+                      width: '100sw',
+                      height: '50px' }
+          };
+        `
+    });
+
+  let decisionLogicURL = createDecisionScriptURL(uuid,
+    {
+      scoreAd:
+        `
+          if (!browserSignals.hasOwnProperty('renderSize')) {
+            throw 'Missing renderSize member in browserSignals.';
+          }
+          if (browserSignals.renderSize.width !== '100sw' ||
+              browserSignals.renderSize.height !== '50px') {
+            throw 'Incorrect renderSize width or height.';
+          }
+      `
+    }
+  );
+
+  await joinGroupAndRunBasicFledgeTestExpectingWinner(
+    test,
+    {
+      uuid: uuid,
+      interestGroupOverrides: {
+        name: uuid,
+        biddingLogicURL: biddingLogicURL,
+        ads: [{ renderURL: createRenderURL(uuid), sizeGroup: 'group1' }],
+        adSizes: { 'size1': { width: '100sw', height: '50px' } },
+        sizeGroups: { 'group1': ['size1'] }
+      },
+      auctionConfigOverrides: {
+        decisionLogicURL: decisionLogicURL
+      }
+    });
+}, 'ScoreAd browserSignals renderSize test.');