diff --git a/include/spdlog/sinks/rotating_file_sink.h b/include/spdlog/sinks/rotating_file_sink.h
index 45fa3bd1..f8c49e75 100644
--- a/include/spdlog/sinks/rotating_file_sink.h
+++ b/include/spdlog/sinks/rotating_file_sink.h
@@ -5,6 +5,7 @@
 
 #include "spdlog/sinks/base_sink.h"
 #include "spdlog/details/file_helper.h"
+#include "spdlog/details/null_mutex.h"
 #include "spdlog/details/synchronous_factory.h"
 
 #include <chrono>