diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8aa596edb5c3a17cc7b929518b36509f7c54cbfb..d5e86018a4b8aae42d3357a5c74757e74f112ee2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -201,7 +201,7 @@ if (WITH_CXX)
   list (APPEND NLOPT_SOURCES stogo/global.cc stogo/linalg.cc stogo/local.cc stogo/stogo.cc stogo/tools.cc stogo/global.h stogo/linalg.h stogo/local.h stogo/stogo_config.h stogo/stogo.h stogo/tools.h)
 endif ()
 
-install (FILES ${NLOPT_HEADERS} DESTINATION ${INSTALL_INCLUDE_DIR})
+install (FILES ${NLOPT_HEADERS} DESTINATION ${RELATIVE_INSTALL_INCLUDE_DIR})
 
 set (nlopt_lib nlopt${NLOPT_SUFFIX})
 add_library (${nlopt_lib} ${NLOPT_SOURCES})