Mawdryn Undead is the third serial of the 20th season of the British science fiction television series Doctor Who. It was originally broadcast in four twice weekly parts on BBC1 from 1 to 9 February 1983.

The twentieth season of British science fiction television series Doctor Who began on 3 January 1983 with the story Arc of Infinity, and ended 16 March 1983 with The King's Demons. A 20th Anniversary special, The Five Doctors, followed in November 1983. John Nathan-Turner produced this series, with Eric Saward script editing.