diff --git a/src/h5core/h5t_octree_private.h b/src/h5core/h5t_octree_private.h
index e8ce92c..e096668 100644
--- a/src/h5core/h5t_octree_private.h
+++ b/src/h5core/h5t_octree_private.h
@@ -14,6 +14,10 @@
 #include "h5core/h5_types.h"
 #include "h5core/h5t_octree.h"
 
+#if defined(PARALLEL_IO)
+#include <mpi.h>
+#endif
+
 #define OCT_MAX_NEIGHBORS 1000
 
 struct h5_oct_point {