diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4e620fc..1058f43 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,7 +9,9 @@ set(CMAKE_AUTORCC ON)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-set(QT_VERSION_MAJOR 6)
+if(NOT DEFINED QT_VERSION_MAJOR)
+    set(QT_VERSION_MAJOR 6)
+endif()
 
 find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Widgets)