diff --git a/tox.ini b/tox.ini
index 263a090b9..102a975a8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,12 +18,15 @@ deps =
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:pep8]
+basepython = python3
 deps = bashate
        flake8
        diskimage-builder
@@ -38,6 +41,7 @@ setenv =
    ELEMENTS_DIR=elements
 
 [testenv:cover]
+basepython = python3
 commands = python setup.py test --coverage --coverage-package-name=instack_undercloud --testr-args='{posargs}'
 
 [flake8]
@@ -53,9 +57,11 @@ exclude = .tox,dist,doc,*.egg,build,elements/puppet-stack-config/install.d/02-pu
 ignore = dibdebugtrace sete setu setpipefail mddocs
 
 [testenv:genconfig]
+basepython = python3
 commands = oslo-config-generator --config-file config-generator/undercloud.conf
 
 [testenv:releasenotes]
+basepython = python3
 commands = bash -c tools/releasenotes_tox.sh
 
 [testenv:lower-constraints]