diff --git a/run_tests.sh b/run_tests.sh
index e25c5eb..8827f8b 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -8,8 +8,9 @@ failed=false
 if [ -z "$TEST_SHELLS" ]; then
   TEST_SHELLS="bash zsh"
 fi
-
 echo "== Will run all tests with following shells: ${TEST_SHELLS}"
+
+builtin cd -P -- "${0%/*}"  # Change to directory this script lives in
 for test in $(find test/lib -name *_test.sh); do
   for shell in $TEST_SHELLS; do
     echo "== Running tests with [$shell]: $test"