1 files changed, 1 insertions, 0 deletions
diff --git a/.travis.yml b/.travis.yml
index e4c8dd8c..eb388687 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -30,6 +30,7 @@ matrix:
             # change this with future releases!
             - debian-sid
           packages:
+            - libssl-dev
     - python: 3.6
       env: TOXENV=py36 OPENSSL_ALPN
       addons: