diff --git a/src/experimental/platform/CMakeLists.txt b/src/experimental/platform/CMakeLists.txt
index a180b148..d4a58d23 100644
--- a/src/experimental/platform/CMakeLists.txt
+++ b/src/experimental/platform/CMakeLists.txt
@@ -67,7 +67,7 @@ target_sources(${MUJOCO_PLATFORM_TARGET_NAME}
         window.h
 )
 
-if(NOT WINDOWS)
+if(NOT WIN32)
   target_sources(${MUJOCO_PLATFORM_TARGET_NAME}
       PUBLIC
           object_launcher_plugin.cc
@@ -85,7 +85,7 @@ elseif(UNIX AND NOT APPLE)
     target_sources(${MUJOCO_PLATFORM_TARGET_NAME} PUBLIC
         file_dialog_zenity.cc
     )
-elseif(WINDOWS)
+elseif(WIN32)
     target_sources(${MUJOCO_PLATFORM_TARGET_NAME} PUBLIC
         file_dialog_win.cc
     )