Companion (Doctor Who)

In the BBC science fiction television series Doctor Who, a "companion" is a character who regularly travels and shares adventures with the series' central character, the alien time traveller known as the Doctor. Typically, a companion encounters the Doctor by chance and is subsequently invited to join them in adventures through time and space. The companion serves as the series' co-lead for the duration of their tenure, and often acts as an audience surrogate by mirroring the viewers' unfamiliarity with science fiction settings and concepts.

When Doctor Who began airing in 1963, companions Ian Chesterton (William Russell) and Barbara Wright (Jacqueline Hill) were the series's primary protagonists, whereas the Doctor served as an elusive but important supporting character. After Russell and Hill left the series, this dynamic was maintained through a succession of new companions—often originating from different eras of history—who filled their roles of a heroic male and an inquisitive young woman. The format changed in 1970 when actor Jon Pertwee introduced an action-oriented "leading man" interpretation of the Doctor which eliminated the need for a male companion. As Pertwee's Doctor was exiled to Earth, his companions were predominantly young women from contemporary England, which became standard in the series going forward. The Doctor has nevertheless continued to travel with male, historical and non-human companions.

As Doctor Who holds a prominent position in British pop culture, the Doctor's companions have attracted attention from critics and the media. Their characterisation has often reflected changing attitudes towards the depiction of women on screen.