diff --git a/.travis.yml b/.travis.yml
index d80d24f32c..b0c0c807cb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,8 @@ mono:
   - 5.2.0
 dotnet: 2.1.200
 script:
+  - sudo apt-get update
+  - sudo apt-get install castxml
   - ./build.sh --target "Travis" --configuration "Release"
 notifications:
   email: false