diff --git a/.travis.yml b/.travis.yml
index 0e441c3..4d32783 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,6 +13,8 @@ matrix:
     - NIXPKGS=https://github.com/NixOS/nixpkgs-channels/archive/nixos-18.09.tar.gz
   - env:
     - NIXPKGS=https://github.com/NixOS/nixpkgs-channels/archive/nixos-19.03.tar.gz
+  - env:
+    - NIXPKGS=https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz
 
 script:
   - nix run nixpkgs.haskellPackages.hlint -c hlint src