diff --git a/samples/SimpleOpenGL/CMakeLists.txt b/samples/SimpleOpenGL/CMakeLists.txt
index e594f2dae..93f389741 100644
--- a/samples/SimpleOpenGL/CMakeLists.txt
+++ b/samples/SimpleOpenGL/CMakeLists.txt
@@ -25,6 +25,7 @@ INCLUDE_DIRECTORIES(
   ${Assimp_SOURCE_DIR}/include
   ${Assimp_SOURCE_DIR}/code
   ${OPENGL_INCLUDE_DIR}
+  ${GLUT_INCLUDE_DIR}
   ${Assimp_SOURCE_DIR}/samples/freeglut/include
 )