diff --git a/.travis.yml b/.travis.yml
index c3cf65f..1d3d1ca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,8 @@ matrix:
     - python: 3.7
       dist: bionic
     - python: pypy
+virtualenv:
+  system_site_packages: true
 install:
   - scripts/install-on-travis.sh
 script: