diff --git a/src/core/ext/filters/client_channel/subchannel_index.cc b/src/core/ext/filters/client_channel/subchannel_index.cc
index ae39ca394e2..1624643d0b4 100644
--- a/src/core/ext/filters/client_channel/subchannel_index.cc
+++ b/src/core/ext/filters/client_channel/subchannel_index.cc
@@ -163,7 +163,7 @@ grpc_subchannel* grpc_subchannel_index_register(grpc_exec_ctx* exec_ctx,
                                                 grpc_subchannel_key* key,
                                                 grpc_subchannel* constructed) {
   grpc_subchannel* c = nullptr;
-  bool need_to_unref_constructed;
+  bool need_to_unref_constructed = false;
 
   while (c == nullptr) {
     need_to_unref_constructed = false;