diff --git a/.travis.yml b/.travis.yml
index 839fc65..e376f04 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -29,6 +29,12 @@ matrix:
       elixir: 1.8
     - otp_release: 22.0
       elixir: 1.8
+    - otp_release: 20.0
+      elixir: 1.9
+    - otp_release: 21.0
+      elixir: 1.9
+    - otp_release: 22.0
+      elixir: 1.9
 sudo: false
 after_script:
   - MIX_ENV=test mix coveralls.travis