diff --git a/tox.ini b/tox.ini
index 9fe295f..19e6567 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = {pypy,pypy3,py27,py35,py36,py37,py38}{,-cryptographyMaster,-cryptographyMinimum}{,-randomorder},py27-twistedMaster,pypi-readme,check-manifest,flake8,docs,coverage-report
+envlist = {pypy,pypy3,py27,py35,py36,py37,py38}{,-cryptographyMaster,-cryptographyMinimum}{,-randomorder},py37-twistedMaster,pypi-readme,check-manifest,flake8,docs,coverage-report
 
 [testenv]
 whitelist_externals =
@@ -22,13 +22,14 @@
     coverage run --parallel -m OpenSSL.debug
     coverage run --parallel -m pytest -v {posargs}
 
-[testenv:py27-twistedMaster]
+[testenv:py37-twistedMaster]
 deps =
     # [tls,conch] syntax doesn't work here so we enumerate all dependencies.
     git+https://github.com/twisted/twisted
     idna
     service_identity
     bcrypt
+setenv =
 passenv = ARCHFLAGS CFLAGS LC_ALL LDFLAGS PATH LD_LIBRARY_PATH TERM
 commands =
     python -c "import OpenSSL.SSL; print(OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION))"