diff --git a/buildout.cfg b/buildout.cfg
index 664238aeb7adb7b0ca152d03828232081b2e291e..d734adf5a4e7b7ee8f8c47231f28da9b0ad089d7 100644
--- a/buildout.cfg
+++ b/buildout.cfg
@@ -21,3 +21,4 @@ script = tests.py
 recipe = collective.recipe.sphinxbuilder
 source = ${buildout:directory}/docs
 build = ${buildout:directory}/built-docs
+interpreter = ${buildout:directory}/bin/python