diff --git a/src/doc/rustc-dev-guide/.travis.yml b/src/doc/rustc-dev-guide/.travis.yml
index bd72a03fc0ba..8fa2f0c1df1a 100644
--- a/src/doc/rustc-dev-guide/.travis.yml
+++ b/src/doc/rustc-dev-guide/.travis.yml
@@ -3,6 +3,8 @@ rust:
 - nightly
 cache:
 - cargo
+- directories:
+  - book/linkcheck/
 before_install:
 - shopt -s globstar
 - MAX_LINE_LENGTH=100 bash ci/check_line_lengths.sh src/**/*.md