diff --git a/gtsam/inference/Ordering.cpp b/gtsam/inference/Ordering.cpp
index 266c54ca6..440d2b828 100644
--- a/gtsam/inference/Ordering.cpp
+++ b/gtsam/inference/Ordering.cpp
@@ -25,8 +25,12 @@
 #include <gtsam/3rdparty/CCOLAMD/Include/ccolamd.h>
 
 #ifdef GTSAM_SUPPORT_NESTED_DISSECTION
+#ifdef GTSAM_USE_SYSTEM_METIS
+#include <metis.h>
+#else
 #include <gtsam/3rdparty/metis/include/metis.h>
 #endif
+#endif
 
 using namespace std;