diff --git a/include/spdlog/details/null_mutex.h b/include/spdlog/details/null_mutex.h
index e3b32204..7b391c37 100644
--- a/include/spdlog/details/null_mutex.h
+++ b/include/spdlog/details/null_mutex.h
@@ -15,7 +15,7 @@ struct null_mutex {
 };
 
 struct null_atomic_int {
-    int value;
+    int value{0};
     null_atomic_int() = default;
 
     explicit null_atomic_int(int new_value)