diff --git a/ros18-base/Makefile.common b/ros18-base/Makefile.common
index 9b3f9801f89c396db5f1217d610c22772d530c5a..d9569d02400ee80abe8811c4c293872989bbbdeb 100644
--- a/ros18-base/Makefile.common
+++ b/ros18-base/Makefile.common
@@ -28,6 +28,7 @@ USE_LANGUAGES?=	c c++
 CMAKE_ARGS+=	-DPYTHON_EXECUTABLE=${PYTHON}
 CMAKE_ARGS+=	-DPYTHON_INCLUDE_DIR=${PYTHON_INCLUDE}
 CMAKE_ARGS+=	-DPYTHON_LIBRARY=${PYTHON_LIB}
+CMAKE_ARGS+=	-DPYTHON_PACKAGES_DIR=site-packages
 
 DEPEND_ABI.python+=	python<3