___Companion_(Doctor_Who)_q.jpg)
In the long-running BBC television science fiction programme Doctor Who and related works, the term "companion" refers to a character who travels with, or shares adventures with, the Doctor. A companion is generally the series' co-lead character alongside the Doctor for the duration of their tenure, and in most Doctor Who stories acts as an audience surrogate by providing the lens through which the viewer is introduced to the story, and often, the series itself.
The companion character often furthers the story by asking questions and getting into trouble; also by helping, rescuing, or challenging the Doctor. This designation is applied to a character by the show's producers and appears in the BBC's promotional material and off-screen fictional terminology. The Doctor also refers to the show's other leads as their "friends" or "assistants"; the British press have also used the latter term.