diff --git a/share/ruby-build/truffleruby-1.0.0-rc12 b/share/ruby-build/truffleruby-1.0.0-rc12
new file mode 100644
index 00000000..4aaf2a1c
--- /dev/null
+++ b/share/ruby-build/truffleruby-1.0.0-rc12
@@ -0,0 +1,7 @@
+install_package "openssl-1.1.0j" "https://www.openssl.org/source/openssl-1.1.0j.tar.gz#31bec6c203ce1a8e93d5994f4ed304c63ccf07676118b6634edded12ad1b3246" mac_openssl --if has_broken_mac_openssl
+
+if is_mac; then
+  install_package "truffleruby-1.0.0-rc12" "https://github.com/oracle/truffleruby/releases/download/vm-1.0.0-rc12/truffleruby-1.0.0-rc12-macos-amd64.tar.gz#3796e42978408826360464234809c71a84e1017227fef688c865b3e636ff3402" truffleruby
+else
+  install_package "truffleruby-1.0.0-rc12" "https://github.com/oracle/truffleruby/releases/download/vm-1.0.0-rc12/truffleruby-1.0.0-rc12-linux-amd64.tar.gz#f84b7fe9e2376962889dbc92c17997954e4e8b8db3e64b07e4220102f47f4aa5" truffleruby
+fi