diff --git a/CMakeLists.txt b/CMakeLists.txt
index 795a7d309..c34ef975b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -257,7 +257,7 @@ endif()
 
 
 find_package(OpenSceneGraph 3.3.4 REQUIRED osgDB osgViewer osgText osgGA osgParticle osgUtil osgFX osgShadow)
-include_directories(${OPENSCENEGRAPH_INCLUDE_DIRS})
+include_directories(SYSTEM ${OPENSCENEGRAPH_INCLUDE_DIRS})
 
 set(USED_OSG_PLUGINS
                     osgdb_bmp