Cowbois ac Injans (Cowboys and Engines) is a Welsh language television drama written by brother and sister Jon Tregenna and Catherine Tregenna which was broadcast on S4C. The series was made by Teledu Opus, which later became Rondo Productions. The title was a pun on the phrase "Cowboys and "Injuns"; "injun", a mis-pronunciation of "Indian" (as in "American Indian") sounds similar to "injan", Welsh for "engine".