diff --git a/.travis.yml b/.travis.yml
index 69a2c25674..97fbac1a27 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,7 @@
 language: c
 
 before_install:
+    - if [[ $TRAVIS_REPO_SLUG == "OpenRCT2/OpenRCT2" ]] && [[ $TRAVIS_PULL_REQUEST != "false" ]] && [[ $TRAVIS_BRANCH == "master" ]]; then echo "Pull requests to master branch are not allowed!" ; exit 1 ; fi
     - if [[ $TRAVIS_OS_NAME == "linux" ]]; then bash scripts/linux/install.sh; export OPENRCT_MAKE_OPTS="-j2 -k all openrct2-cli" ; fi
     - if [[ $TRAVIS_OS_NAME == "osx" ]]; then sudo gem install xcpretty-travis-formatter; fi