diff --git a/kokoro/macos/ruby25/build.sh b/kokoro/macos/ruby25/build.sh
index 38e90aa..ba2d0a4 100755
--- a/kokoro/macos/ruby25/build.sh
+++ b/kokoro/macos/ruby25/build.sh
@@ -6,6 +6,8 @@
 cd $(dirname $0)/../../..
 
 # Prepare worker environment to run tests
+KOKORO_INSTALL_RUBY=yes
+KOKORO_INSTALL_RVM=yes
 source kokoro/macos/prepare_build_macos_rc
 
 ./tests.sh ruby25