diff --git a/tox.ini b/tox.ini
index 44fdaebc8f..e5cf82f239 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,9 +20,11 @@ commands =
   python setup.py test --slowest --testr-args='{posargs}'
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper -t tests {posargs}
 
 [testenv:cover]
+basepython = python3
 setenv = VIRTUAL_ENV={envdir}
          NOSE_WITH_COVERAGE=1
          NOSE_COVER_BRANCHES=1
@@ -31,6 +33,7 @@ setenv = VIRTUAL_ENV={envdir}
 commands = python setup.py testr --coverage --testr-args='{posargs}'
 
 [testenv:pep8]
+basepython = python3
 # sphinx needs to be installed to make doc8 work properly
 deps =
     {[testenv]deps}
@@ -45,9 +48,11 @@ commands =
   yamllint .
 
 [testenv:bandit]
+basepython = python3
 commands = bandit -r ansible kolla_ansible tests tools
 
 [testenv:venv]
+basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/test-requirements.txt
@@ -55,6 +60,7 @@ deps =
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 deps =
    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
    -r{toxinidir}/requirements.txt
@@ -64,6 +70,7 @@ commands =
   sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:deploy-guide]
+basepython = python3
 deps =
    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
    -r{toxinidir}/requirements.txt
@@ -74,11 +81,13 @@ commands =
   sphinx-build -a -E -W -d deploy-guide/build/doctrees -b html deploy-guide/source deploy-guide/build/html
 
 [testenv:setupenv]
+basepython = python3
 commands =
   {toxinidir}/tools/setup_gate.sh
   {toxinidir}/tools/dump_info.sh
 
 [testenv:releasenotes]
+basepython = python3
 deps =
    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
    -r{toxinidir}/requirements.txt