diff --git a/NumLib/Exceptions.h b/NumLib/Exceptions.h
index b333a77e02754e36c1da14ec5c8d6e6ad2b38ab7..cb10f8ea7f20d95d2b40fb259811f17bd8d7b8e3 100644
--- a/NumLib/Exceptions.h
+++ b/NumLib/Exceptions.h
@@ -17,7 +17,7 @@ namespace NumLib
 {
 struct AssemblyException : public std::runtime_error
 {
-    AssemblyException(std::string const& reason)
+    explicit AssemblyException(std::string const& reason)
         : std::runtime_error{"Error in process' assembly: " + reason} {};
 };
 }  // namespace NumLib