The fifteenth season of British science fiction television series Doctor Who began on 3 September 1977 with the episode Horror of Fang Rock, and ended with The Invasion of Time. The fourth series for the Fourth Doctor, new producer Graham Williams became producer for this series, while Robert Holmes left script editing for Anthony Read midway through.

Horror of Fang Rock is the first serial of the 15th season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts on BBC1 from 3 to 24 September 1977.