diff --git a/include/spdlog/sinks/ringbuffer_sink.h b/include/spdlog/sinks/ringbuffer_sink.h
index ee6ef555..16f7cb56 100644
--- a/include/spdlog/sinks/ringbuffer_sink.h
+++ b/include/spdlog/sinks/ringbuffer_sink.h
@@ -6,6 +6,7 @@
 #include "spdlog/sinks/base_sink.h"
 #include "spdlog/details/circular_q.h"
 #include "spdlog/details/log_msg_buffer.h"
+#include "spdlog/details/null_mutex.h"
 
 #include <mutex>
 #include <string>