diff --git a/proxygen/lib/http/webtransport/QuicWtSession.cpp b/proxygen/lib/http/webtransport/QuicWtSession.cpp
index 988dd8aed2..daf565ff24 100644
--- a/proxygen/lib/http/webtransport/QuicWtSession.cpp
+++ b/proxygen/lib/http/webtransport/QuicWtSession.cpp
@@ -373,7 +373,12 @@ void QuicWtSessionBase::StreamManagerCallback::eventsAvailableImpl() noexcept {
     if (streamData.fin) {
       sock->setStopSendingCallback(streamId, nullptr);
     } else if (isWtStreamEgressFcBlocked(sess.sm_, *wh)) {
-      sess.quicSocket_->notifyPendingWriteOnStream(streamId, &sess);
+      // The cached window may lag the peer's MAX_STREAM_DATA; refreshing it
+      // here saves a loop iteration through notifyPendingWriteOnStream.
+      grantMaxData(*sock, sess.sm_, *wh);
+      if (isWtStreamEgressFcBlocked(sess.sm_, *wh)) {
+        sess.quicSocket_->notifyPendingWriteOnStream(streamId, &sess);
+      }
     }
   }
 }
diff --git a/proxygen/lib/http/webtransport/test/QuicWtSessionTest.cpp b/proxygen/lib/http/webtransport/test/QuicWtSessionTest.cpp
index e606ea360c..4f748aa6cd 100644
--- a/proxygen/lib/http/webtransport/test/QuicWtSessionTest.cpp
+++ b/proxygen/lib/http/webtransport/test/QuicWtSessionTest.cpp
@@ -846,6 +846,27 @@ TEST_F(QuicWtSessionTest, WriteFlowControlBlocked) {
   EXPECT_TRUE(stream.writeEOF);
 }
 
+TEST_F(QuicWtSessionTest, WriteRefreshesStaleFlowControl) {
+  auto handle = session_->createUniStream();
+  ASSERT_TRUE(handle.hasValue());
+  const auto id = handle.value()->getID();
+  socketDriver_.setConnectionFlowControlWindow(
+      std::numeric_limits<uint64_t>::max());
+
+  // Peer raised MAX_STREAM_DATA after creation; the cached window is stale.
+  constexpr size_t kDataLength = 65'537;
+  socketDriver_.setStreamFlowControlWindow(id, kDataLength);
+
+  handle.value()->writeStreamData(
+      folly::IOBuf::copyBuffer(std::string(kDataLength, 'a')), true, nullptr);
+  eventBase_.loopOnce();
+
+  auto& stream = socketDriver_.streams_[id];
+  EXPECT_EQ(stream.writeBuf.chainLength(), kDataLength);
+  EXPECT_TRUE(stream.writeEOF);
+  EXPECT_EQ(stream.pendingWriteCb.stream, nullptr);
+}
+
 /**
  * Unsure if the following is possible in production (i.e. QuicTransportBase) --
  * but it tests when a ::writeChain fails without a prior ::readError or