diff --git a/doc/Makefile b/doc/Makefile
index 747126b3bf43d3a4e7b1f016351124b881936c41..05f8ff34b1e0de5c68ac257c5c8697c08a24563c 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -4,7 +4,7 @@
 # You can set these variables from the command line, and also
 # from the environment for the first two.
 SPHINXOPTS    ?= -n
-SPHINXBUILD   ?= sphinx-build
+SPHINXBUILD   ?= python $(shell which sphinx-build)
 SOURCEDIR     = .
 BUILDDIR      = _build