diff --git a/quic/core/quic_config.cc b/quic/core/quic_config.cc
index b396020..30a5e2b 100644
--- a/quic/core/quic_config.cc
+++ b/quic/core/quic_config.cc
@@ -1006,7 +1006,17 @@
     max_unidirectional_streams_.ToHandshakeMessage(out);
     ack_delay_exponent_.ToHandshakeMessage(out);
   }
-  max_ack_delay_ms_.ToHandshakeMessage(out);
+  if (GetQuicReloadableFlag(quic_dont_send_max_ack_delay_if_default)) {
+    QUIC_RELOADABLE_FLAG_COUNT(quic_dont_send_max_ack_delay_if_default);
+    if (max_ack_delay_ms_.GetSendValue() != kDefaultDelayedAckTimeMs) {
+      // Only send max ack delay if it is using a non-default value, because
+      // the default value is used by QuicSentPacketManager if it is not
+      // sent during the handshake, and we want to save bytes.
+      max_ack_delay_ms_.ToHandshakeMessage(out);
+    }
+  } else {
+    max_ack_delay_ms_.ToHandshakeMessage(out);
+  }
   bytes_for_connection_id_.ToHandshakeMessage(out);
   initial_round_trip_time_us_.ToHandshakeMessage(out);
   initial_stream_flow_control_window_bytes_.ToHandshakeMessage(out);