diff --git a/modules/mono/csharp_script.cpp b/modules/mono/csharp_script.cpp
index 44993674c1d7..1c41b1777849 100644
--- a/modules/mono/csharp_script.cpp
+++ b/modules/mono/csharp_script.cpp
@@ -647,6 +647,8 @@ void CSharpLanguage::reload_assemblies_if_needed(bool p_soft_reload) {
 			name = "UnnamedProject";
 		}
 
+		name += ".dll";
+
 		if (proj_assembly) {
 			String proj_asm_path = proj_assembly->get_path();