diff --git a/tox.ini b/tox.ini
index d53ceb9fa61..b07ec9770da 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,14 +23,17 @@ commands = stestr run {posargs}
 # mode. To do this define the TRACE_FAILONLY environmental variable.
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper -t neutron/tests {posargs}
 
 [testenv:common]
+basepython = python3
 # Fake job to define environment variables shared between dsvm/non-dsvm jobs
 setenv = OS_TEST_TIMEOUT={env:OS_TEST_TIMEOUT:180}
 commands = false
 
 [testenv:dsvm]
+basepython = python3
 # Fake job to define environment variables shared between dsvm jobs
 setenv = OS_SUDO_TESTING=1
          OS_ROOTWRAP_CMD=sudo {envdir}/bin/neutron-rootwrap {envdir}/etc/neutron/rootwrap.conf
@@ -75,6 +78,7 @@ commands =
   stestr run {posargs}
 
 [testenv:dsvm-fullstack]
+basepython = python2.7
 setenv = {[testenv]setenv}
          {[testenv:common]setenv}
          {[testenv:dsvm]setenv}
@@ -97,6 +101,7 @@ commands =
   {[testenv:dsvm-fullstack]commands}
 
 [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
 
@@ -133,13 +138,16 @@ commands =
   coverage xml -o cover/coverage.xml
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:linkcheck]
+basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b linkcheck doc/source doc/build/linkcheck
 
@@ -170,6 +178,7 @@ import_exceptions = neutron._i18n
 local-check-factory = neutron.hacking.checks.factory
 
 [testenv:bandit]
+basepython = python3
 # B104: Possible binding to all interfaces
 # B111: Execute with run_as_root=True identified, possible security issue
 # B311: Standard pseudo-random generators are not suitable for security/cryptographic purpose
@@ -177,6 +186,7 @@ deps = -r{toxinidir}/test-requirements.txt
 commands = bandit -r neutron -x tests -n5 -s B104,B111,B311
 
 [testenv:bashate]
+basepython = python3
 commands = bash -c "find {toxinidir}             \
          -not \( -type d -name .tox\* -prune \)  \
          -not \( -type d -name .venv\* -prune \) \
@@ -189,11 +199,13 @@ commands = bash -c "find {toxinidir}             \
          -print0 | xargs -0 bashate -v -iE006 -eE005,E042,E043"
 
 [testenv:genconfig]
+basepython = python3
 commands = {toxinidir}/tools/generate_config_file_samples.sh
 
 # 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