diff --git a/.travis.yml b/.travis.yml
index 7f6f2a04b..29bdd5655 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -33,14 +33,14 @@ matrix:
   # https://github.com/hvr/multi-ghc-travis
   - env: BUILD=cabal GHCVER=7.8.4 CABALVER=1.18
     compiler: ": #GHC 7.8.4"
-    addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
+    addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4,happy-1.19.5], sources: [hvr-ghc]}}
   - env: BUILD=cabal GHCVER=7.10.3 CABALVER=1.22
     compiler: ": #GHC 7.10.3"
-    addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.3], sources: [hvr-ghc]}}
+    addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.3,happy-1.19.5], sources: [hvr-ghc]}}
 
   - env: BUILD=cabal GHCVER=8.0.1 CABALVER=1.24
     compiler: ": #GHC 8.0.1"
-    addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.1], sources: [hvr-ghc]}}
+    addons: {apt: {packages: [cabal-install-1.24,ghc-8.0.1,happy-1.19.5], sources: [hvr-ghc]}}
 
   # Build with the newest GHC and cabal-install. This is an accepted failure,
   # see below.