diff --git a/modules/audio_coding/neteq/nack_tracker.cc b/modules/audio_coding/neteq/nack_tracker.cc
index 35afb736c8..04cc5b52e8 100644
--- a/modules/audio_coding/neteq/nack_tracker.cc
+++ b/modules/audio_coding/neteq/nack_tracker.cc
@@ -225,8 +225,12 @@ int64_t NackTracker::TimeToPlay(uint32_t timestamp) const {
 std::vector<uint16_t> NackTracker::GetNackList(int64_t round_trip_time_ms) {
   RTC_DCHECK_GE(round_trip_time_ms, 0);
   std::vector<uint16_t> sequence_numbers;
-  if (config_.require_valid_rtt && round_trip_time_ms == 0) {
-    return sequence_numbers;
+  if (round_trip_time_ms == 0) {
+    if (config_.require_valid_rtt) {
+      return sequence_numbers;
+    } else {
+      round_trip_time_ms = config_.default_rtt_ms;
+    }
   }
   if (packet_loss_rate_ >
       static_cast<uint32_t>(config_.max_loss_rate * (1 << 30))) {
diff --git a/modules/audio_coding/neteq/nack_tracker.h b/modules/audio_coding/neteq/nack_tracker.h
index 0cc95b0882..14ba2166d1 100644
--- a/modules/audio_coding/neteq/nack_tracker.h
+++ b/modules/audio_coding/neteq/nack_tracker.h
@@ -111,6 +111,8 @@ class NackTracker {
     bool never_nack_multiple_times = false;
     // Only nack if the RTT is valid.
     bool require_valid_rtt = false;
+    // Default RTT to use unless `require_valid_rtt` is set.
+    int default_rtt_ms = 100;
     // Do not nack if the loss rate is above this value.
     double max_loss_rate = 1.0;
   };