diff --git a/waflib/Tools/python.py b/waflib/Tools/python.py
index b8c29829..de392248 100644
--- a/waflib/Tools/python.py
+++ b/waflib/Tools/python.py
@@ -591,7 +591,7 @@ def configure(conf):
 	if getattr(Options.options, 'nopycache', None):
 		v.NOPYCACHE=Options.options.nopycache
 
-	conf.find_program('python', var='PYTHON', value=getattr(Options.options, 'python', sys.executable))
+	conf.find_program('python', var='PYTHON', value=getattr(Options.options, 'python', None) or sys.executable)
 
 	v.PYFLAGS = ''
 	v.PYFLAGS_OPT = '-O'