diff --git a/tox.ini b/tox.ini
index fba2f4c7..522a323a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,6 +29,7 @@ commands =
   stestr run {posargs}
 
 [testenv:cover]
+basepython = python3
 setenv =
     PYTHON=coverage run --source monasca_persister --parallel-mode
 commands =
@@ -38,9 +39,11 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper -t monasca_persister/tests {posargs}
 
 [testenv:pep8]
+basepython = python3
 deps =
   {[testenv]deps}
 commands =
@@ -49,15 +52,18 @@ commands =
   python setup.py check --restructuredtext --strict
 
 [testenv:genconfig]
+basepython = python3
 description = Generates sample configuration file for monasca-persister
 whitelist_externals = bash
 commands =
   oslo-config-generator --config-file=config-generator/persister.conf
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [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
@@ -66,6 +72,7 @@ deps = bindep
 commands = bindep test
 
 [testenv:flake8]
+basepython = python3
 commands =
     flake8 monasca_persister