diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f76468695a77..993608826518 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -42,7 +42,7 @@ jobs:
         python-version: ${{ matrix.python }}
         architecture: ${{ matrix.arch }}
     - name: install tox
-      run: pip install --upgrade setuptools tox==3.9.0
+      run: pip install --upgrade setuptools 'virtualenv<20' tox==3.9.0
     - name: setup tox environment
       run: tox -e ${{ matrix.toxenv }} --notest
     - name: test
diff --git a/.travis.yml b/.travis.yml
index ee6c107f49f1..c0f275bfde8b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -81,6 +81,7 @@ jobs:
 
 install:
 - pip install -U pip setuptools
+- pip install -U 'virtualenv<20'
 - pip install -U tox==3.9.0
 - tox --notest
 
diff --git a/appveyor.yml b/appveyor.yml
index 06d4a480b280..4abe31728f56 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -14,7 +14,7 @@ environment:
 
 install:
     - "git submodule update --init mypy/typeshed"
-    - "%PYTHON%\\python.exe -m pip install -U setuptools tox==3.9.0"
+    - '%PYTHON%\\python.exe -m pip install -U setuptools "virtualenv<20" tox==3.9.0'
     - "%PYTHON%\\python.exe -m tox -e py37 --notest"
 
 build: off
diff --git a/test-requirements.txt b/test-requirements.txt
index 649438743053..f339c593e47b 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -12,6 +12,6 @@ pytest-forked>=1.0.0,<1.1.0
 pytest-cov>=2.4.0
 typing>=3.5.2; python_version < '3.5'
 py>=1.5.2
-virtualenv
+virtualenv<20
 setuptools
 importlib-metadata==0.20