diff --git a/libraries/custom_appbase/include/eosio/chain/exec_pri_queue.hpp b/libraries/custom_appbase/include/eosio/chain/exec_pri_queue.hpp
index 4e2f0263ad..41716284af 100644
--- a/libraries/custom_appbase/include/eosio/chain/exec_pri_queue.hpp
+++ b/libraries/custom_appbase/include/eosio/chain/exec_pri_queue.hpp
@@ -3,6 +3,7 @@
 
 #include <condition_variable>
 #include <mutex>
+#include <optional>
 #include <queue>
 
 namespace appbase {