We document fossil bones (caudal vertebrae, femur) of a tenontosaur (cf. Tenontosaurus sp.) from the Aptian/Albian Yucca Formation in far West Texas. This southernmost record of a tenontosaur in the Western Interior is about 400 km east of Arizona records and about 900 km southwest of its records in north-central Texas. The Yucca Formation record confirms the Aptian/Albian boundary age data that constrain other Tenontosaurus records. The West Texas Tenontosaurus thus adds to the distribution of one of the dominant dinosaurian herbivores of the Aptian-Albian in the Western Interior.