diff --git a/include/spdlog/details/mpmc_blocking_q.h b/include/spdlog/details/mpmc_blocking_q.h
index 9a922e04..cf34d225 100644
--- a/include/spdlog/details/mpmc_blocking_q.h
+++ b/include/spdlog/details/mpmc_blocking_q.h
@@ -32,6 +32,7 @@ public:
 
     size_t overrun_counter() const
     {
+      std::unique_lock<std::mutex> lock(queue_mutex_);
       return q_.overrun_counter();
     }