It's lonely business, being basically immortal and traveling time and space in a body that never ages. Which is why the last remaining Timelord always brings along a friend! Usually a woman, usually from Earth, always somebody kind of amazing. Here, we rank them from mildly interesting to all-out timey-wimey.
We're sticking to the current series (Ninth, Tenth, Eleventh and Twelfth Doctors). Also considered are companions who joined for just one episode of a special.
Photo Credits: Mike Coppola/Getty Images; HBO; SHOWTIME; Jessica Miglio, Photo by Jessica Miglio; Annette Brown, Annette Brown/The CW; Bob Mahoney, Bob Mahoney/The CW; CBS; Courtesy Netflix; Ben Mark Holzberg/Syfy