diff --git a/simulation/halsim_ws_core/src/main/native/include/WSProviderContainer.h b/simulation/halsim_ws_core/src/main/native/include/WSProviderContainer.h
index 5ea8cb693f..6c51b46940 100644
--- a/simulation/halsim_ws_core/src/main/native/include/WSProviderContainer.h
+++ b/simulation/halsim_ws_core/src/main/native/include/WSProviderContainer.h
@@ -6,6 +6,7 @@
 
 #include <functional>
 #include <memory>
+#include <mutex>
 #include <shared_mutex>
 
 #include <wpi/StringMap.h>