diff --git a/tox.ini b/tox.ini
index fdbe5f3..2ca2012 100644
--- a/tox.ini
+++ b/tox.ini
@@ -32,6 +32,7 @@ setenv =
 
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands=
     bash -c "rm -rf doc/build"
@@ -45,6 +46,7 @@ extensions = .rst
 
 
 [testenv:releasenotes]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands =
     sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
@@ -52,11 +54,13 @@ commands =
 
 # environment used by the -infra templated docs job
 [testenv:venv]
+basepython = python3
 commands =
     {posargs}
 
 
 [testenv:pep8]
+basepython = python3
 commands =
     bash -c "{toxinidir}/tests/common/test-pep8.sh"