diff --git a/tools/ocaml/Makefile b/tools/ocaml/Makefile
index 2a36e7bc8c..36e5f9e320 100644
--- a/tools/ocaml/Makefile
+++ b/tools/ocaml/Makefile
@@ -10,6 +10,10 @@ SUBDIRS_PROGRAMS = xenstored
 
 SUBDIRS = $(SUBDIRS_LIBS) $(SUBDIRS_PROGRAMS)
 
+.NOTPARALLEL:
+# targets here must be run in order, otherwise we can try
+# to build programs before the libraries are done
+
 .PHONY: all
 all: build