diff --git a/gui/CMakeLists.txt b/gui/CMakeLists.txt
index 35cf7e8..352af9a 100644
--- a/gui/CMakeLists.txt
+++ b/gui/CMakeLists.txt
@@ -37,5 +37,5 @@ target_link_libraries(chiaki FFMPEG::avcodec)
 target_link_libraries(chiaki Qt5::Core Qt5::Widgets Qt5::Gui Qt5::Multimedia)
 if(CHIAKI_GUI_ENABLE_QT_GAMEPAD)
 	target_link_libraries(chiaki Qt5::Gamepad)
-	target_compile_definitions(chiaki CHIAKI_GUI_ENABLE_QT_GAMEPAD)
+	target_compile_definitions(chiaki PRIVATE CHIAKI_GUI_ENABLE_QT_GAMEPAD)
 endif()