Inferno is the fourth and final serial of the seventh season of the British science fiction television series Doctor Who, which was first broadcast in seven weekly parts on BBC1 from 9 May to 20 June 1970. The serial remains the last time a Doctor Who story was transmitted in seven episodes. This serial was also the last regular appearance of Caroline John in the role of Liz Shaw.

The seventh season of British science fiction television series Doctor Who began on 3 January 1970 with Jon Pertwee's first story Spearhead from Space and ended with Inferno. The first season to be made in colour, it marked the beginning of Barry Letts's five seasons as series producer, but it has been described as "essentially devised" by his predecessor, Derrick Sherwin, who produced the opening story. The season sees the beginning of the Doctor's exile to Earth by the Time Lords and his attachment to UNIT as its scientific advisor.