diff --git a/quiche/common/btree_scheduler.h b/quiche/common/btree_scheduler.h
index 753eda2..3db2a6c 100644
--- a/quiche/common/btree_scheduler.h
+++ b/quiche/common/btree_scheduler.h
@@ -93,7 +93,7 @@
     ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS Priority priority;
     // If present, the sequence number with which the stream is currently
     // scheduled.  If absent, indicates that the stream is not scheduled.
-    std::optional<int> current_sequence_number;
+    std::optional<int> current_sequence_number = std::nullopt;
 
     bool scheduled() const { return current_sequence_number.has_value(); }
   };