diff --git a/quic/api/QuicTransportBase.cpp b/quic/api/QuicTransportBase.cpp
index 920f2b8ba..3e48f6496 100644
--- a/quic/api/QuicTransportBase.cpp
+++ b/quic/api/QuicTransportBase.cpp
@@ -2770,6 +2770,11 @@ void QuicTransportBase::scheduleAckTimeout() {
     if (!ackTimeout_.isScheduled()) {
       auto factoredRtt = std::chrono::duration_cast<std::chrono::microseconds>(
           kAckTimerFactor * conn_->lossState.srtt);
+      // If we are using ACK_FREQUENCY, disable the factored RTT heuristic
+      // and only use the update max ACK delay.
+      if (conn_->ackStates.appDataAckState.ackFrequencySequenceNumber) {
+        factoredRtt = conn_->ackStates.maxAckDelay;
+      }
       auto& wheelTimer = getEventBase()->timer();
       auto timeout = timeMax(
           std::chrono::duration_cast<std::chrono::microseconds>(
diff --git a/quic/api/test/QuicTransportTest.cpp b/quic/api/test/QuicTransportTest.cpp
index 75ee3b6d0..cae4c729a 100644
--- a/quic/api/test/QuicTransportTest.cpp
+++ b/quic/api/test/QuicTransportTest.cpp
@@ -4343,6 +4343,36 @@ TEST_F(QuicTransportTest, ScheduleAckTimeout) {
   EXPECT_NEAR(transport_->getAckTimeout()->getTimeRemaining().count(), 25, 5);
 }
 
+TEST_F(QuicTransportTest, ScheduleAckTimeoutSRTTFactor) {
+  transport_->getConnectionState().lossState.srtt = 50ms;
+  EXPECT_FALSE(transport_->getAckTimeout()->isScheduled());
+  transport_->getConnectionState().pendingEvents.scheduleAckTimeout = true;
+  transport_->onNetworkData(
+      SocketAddress("::1", 10003),
+      NetworkData(
+          IOBuf::copyBuffer("Never on time, always timeout"), Clock::now()));
+  EXPECT_TRUE(transport_->getAckTimeout()->isScheduled());
+  EXPECT_NEAR(
+      transport_->getAckTimeout()->getTimeRemaining().count(), 50 / 4, 2);
+}
+
+TEST_F(QuicTransportTest, ScheduleAckTimeoutAckFreq) {
+  transport_->getConnectionState().lossState.srtt = 50ms;
+  transport_->getConnectionState().transportSettings.minAckDelay = 1ms;
+  transport_->getConnectionState()
+      .ackStates.appDataAckState.ackFrequencySequenceNumber = 1;
+  transport_->getConnectionState().ackStates.maxAckDelay = 50ms / 3;
+  EXPECT_FALSE(transport_->getAckTimeout()->isScheduled());
+  transport_->getConnectionState().pendingEvents.scheduleAckTimeout = true;
+  transport_->onNetworkData(
+      SocketAddress("::1", 10003),
+      NetworkData(
+          IOBuf::copyBuffer("Never on time, always timeout"), Clock::now()));
+  EXPECT_TRUE(transport_->getAckTimeout()->isScheduled());
+  EXPECT_NEAR(
+      transport_->getAckTimeout()->getTimeRemaining().count(), 50 / 3, 2);
+}
+
 TEST_F(QuicTransportTest, ScheduleAckTimeoutFromMaxAckDelay) {
   // Make srtt large so we will use maxAckDelay
   transport_->getConnectionState().lossState.srtt = 25000000us;