Ethelmaer, Elmer, or Aelmer (died 1137), also called Herlewin, was an English ascetic writer. Ethelmaer was made prior of Christ Church, Canterbury, in 1128, and is said to have been a man of great piety and simplicity. His simplicity led him to take the part of Archbishop in a dispute he had with the convent in 1136 about the church of St. Martin at Dover. He died 11 May 1137.