Nyssa is a fictional character in the long-running British science fiction television series Doctor Who. She is played by Sarah Sutton. Although Nyssa was created by writer Johnny Byrne for a single Fourth Doctor serial The Keeper of Traken, the production team subsequently decided she should be retained as a continuing character. Nyssa returned in the following serial, Logopolis, in which the Fourth Doctor regenerated, and remained as a companion of the Fifth Doctor. She was a regular in the programme from 1981 to 1983.