diff --git a/goal_tools/python3_first/toxsettings.py b/goal_tools/python3_first/toxsettings.py
new file mode 100644
index 0000000..57570a3
--- /dev/null
+++ b/goal_tools/python3_first/toxsettings.py
@@ -0,0 +1,124 @@
+#!/usr/bin/env python3
+
+import configparser
+import logging
+import os.path
+import subprocess
+
+from goal_tools import governance
+
+from cliff import lister
+
+LOG = logging.getLogger(__name__)
+
+ENVS = [
+    'docs',
+    'linters',
+    'lower-constraints',
+    'pep8',
+    'releasenotes',
+    'venv'
+]
+
+
+def get_tox_config(repo_dir):
+    LOG.debug('getting tox settings in %s', repo_dir)
+    try:
+        result = subprocess.run(
+            ['tox', '--showconfig'],
+            check=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.DEVNULL,
+            cwd=repo_dir,
+        )
+    except subprocess.CalledProcessError:
+        LOG.info('unable to fetch tox settings for %s', repo_dir)
+        return None
+    text = result.stdout.decode('utf-8')
+    # The preamble of the output is not INI format,
+    # so we skip over it by looking for a double blank line.
+    return text.partition('\n\n')[-1]
+
+
+def check_one(repo_base_dir, repo):
+    repo_dir = os.path.join(os.path.expanduser(repo_base_dir), repo)
+    if not os.path.exists(os.path.join(repo_dir, 'tox.ini')):
+        LOG.info('skipping %s', repo)
+        return
+    LOG.info('scanning %s', repo)
+    config = get_tox_config(repo_dir)
+    LOG.debug(config)
+    if config is None:
+        return
+    parser = configparser.ConfigParser()
+    parser.read_string(config, repo)
+    for env in ENVS:
+        section = 'testenv:{}'.format(env)
+        if not parser.has_section(section):
+            LOG.debug('%s has no section %s', repo, section)
+            continue
+        if not parser.has_option(section, 'basepython'):
+            yield (section, 'not set')
+            continue
+        value = parser.get(section, 'basepython')
+        if 'python3' not in value:
+            yield (section, 'set to {!r}'.format(value))
+            continue
+        yield (section, 'OK')
+
+
+class ToxMissingPy3(lister.Lister):
+    "list the tox environments missing python3 settings"
+
+    def get_parser(self, prog_name):
+        parser = super().get_parser(prog_name)
+        parser.add_argument(
+            '--repo-base-dir',
+            default='~/repos',
+            help='base directory where repositories are cloned (%(default)s)',
+        )
+        parser.add_argument(
+            '--project-list',
+            default=governance.PROJECTS_LIST,
+            help='URL for governance projects.yaml',
+        )
+        parser.add_argument(
+            '--team',
+            help='limit search to one team',
+        )
+        parser.add_argument(
+            '--errors-only', '-e',
+            default=False,
+            action='store_true',
+            help='only show mistakes',
+        )
+        return parser
+
+    def take_action(self, parsed_args):
+        columns = ('Team', 'Repo', 'Env', 'Status')
+
+        gov_dat = governance.Governance(url=parsed_args.project_list)
+        if parsed_args.team:
+            repos = gov_dat.get_repos_for_team(parsed_args.team)
+        else:
+            repos = gov_dat.get_repos()
+
+        teams_and_repos = sorted(
+            (gov_dat.get_repo_owner(r), r)
+            for r in repos
+        )
+
+        data = [
+            (team, r, env, status)
+            for team, r in teams_and_repos
+            for env, status in check_one(parsed_args.repo_base_dir, r)
+        ]
+
+        if parsed_args.errors_only:
+            data = [
+                r
+                for r in data
+                if r[-1] != 'OK'
+            ]
+
+        return (columns, data)
diff --git a/setup.cfg b/setup.cfg
index 51cae42..58d4e62 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -61,6 +61,7 @@ python3_first =
     patches list = goal_tools.python3_first.patches:PatchesList
     patches count = goal_tools.python3_first.patches:PatchesCount
     migration announce = goal_tools.python3_first.repos:MigrationAnnounce
+    tox missing = goal_tools.python3_first.toxsettings:ToxMissingPy3
 
 [wheel]
 universal = 1