diff --git a/CMakeLists.txt b/CMakeLists.txt
index 743009e5a..649e3e10c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -958,8 +958,8 @@ endif()
 
 if (WITH_RENDER_METAL)
   if (APPLE)
-    list(APPEND GUI_SOURCES src/gui/render/renderMetal.cpp)
-    list(APPEND GUI_SOURCES extern/imgui_patched/backends/imgui_impl_metal.cpp)
+    list(APPEND GUI_SOURCES src/gui/render/renderMetal.mm)
+    list(APPEND GUI_SOURCES extern/imgui_patched/backends/imgui_impl_metal.mm)
     list(APPEND DEPENDENCIES_DEFINES HAVE_RENDER_METAL)
     list(APPEND DEPENDENCIES_LIBRARIES "-framework Metal")
     list(APPEND DEPENDENCIES_LIBRARIES "-framework MetalKit")