The triangle keelback (Xenochrophis trianguligerus) is a species of snake found in Brunei Darussalam, Burma (Myanmar), Cambodia, India (Nicobar Islands; Arunachal Pradesh (Deban - Changlang district)), Indonesia (Nias, Mentawai, Sumatra, Laos, Malaysia (Malaya and East Malaysia), Singapore, Thailand, and Vietnam.
The type locality is Java.