diff --git a/.travis.yml b/.travis.yml
index 11894eb..b958eca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -237,6 +237,8 @@
           - libglib2.0-dev
           - libgnutls28-dev
           - ninja-build
+          - flex
+          - bison
       env:
         - CONFIG="--disable-containers --disable-system"