diff --git a/tox.ini b/tox.ini
index f038c853e..d21048b1b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,11 +24,13 @@ commands = python -m pre_commit run --source HEAD^ --origin HEAD
 
 # deprecated: use linters instead. kept only as a convenience alias
 [testenv:pep8]
+basepython = python3
 envdir = {toxworkdir}/linters
 whitelist_externals = {[testenv:linters]whitelist_externals}
 commands = {[testenv:linters]commands}
 
 [testenv:cireport]
+basepython = python3
 passenv =
   SSH_AUTH_SOCK
 commands = python scripts/tripleo-jobs-gerrit.py {posargs}
@@ -36,6 +38,7 @@ commands = python scripts/tripleo-jobs-gerrit.py {posargs}
 # This environment can be used to quickly validate that all needed system
 # packages required to successfully execute test targets are installed
 [testenv:bindep]
+basepython = python3
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system
 # dependencies are missing! This also means that bindep must be installed
@@ -50,6 +53,7 @@ changedir = scripts/emit_releases_file
 commands = pytest {posargs:--cov=emit_releases_file}
 
 [testenv:py35]
+basepython = python3
 deps={[testenv]deps}
 changedir = {[testenv:py27]changedir}
 commands = {[testenv:py27]commands}