diff --git a/include/spdlog/sinks/async_sink.h b/include/spdlog/sinks/async_sink.h
index 30fa744f7..8b408ebde 100644
--- a/include/spdlog/sinks/async_sink.h
+++ b/include/spdlog/sinks/async_sink.h
@@ -13,7 +13,7 @@
 // The worker thread is terminated when the async_sink is destroyed.
 
 namespace spdlog::details {  // forward declaration
-template <typename Mutex>
+template <typename T>
 class mpmc_blocking_queue;
 }