diff --git a/doc/Makefile b/doc/Makefile
index 912e73f6..5a93ba54 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -1,5 +1,7 @@
 .PHONY: install uninstall clean
 
+.NOTPARALLEL:
+
 SOURCE_DIR := source
 BUILD_DIR := build