diff --git a/docs/Makefile b/docs/Makefile
index a6546d0..8358bed 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -7,7 +7,7 @@ SPHINXBUILD   = sphinx-build
 PAPER         =
 SRCDIR        = source
 BUILDDIR      = build
-PYTHON        = python
+PYTHON        = python3
 
 # Internal variables.
 PAPEROPT_a4     = -D latex_paper_size=a4