Brainiac 5 (Querl Dox) is a superhero appearing in comics published by DC Comics. He is from the planet Colu and is a long-standing member of the Legion of Super-Heroes in the 30th and 31st centuries.

The first live-action version of the character appeared as a regular character in the fifth season and a recurring character in the seventh season of Smallville, portrayed by James Marsters. Brainiac 5 was introduced in the third season of the Arrowverse series Supergirl, portrayed by Jesse Rath. He became part of the main cast starting in the fourth season. An alternate universe female version of Brainiac 5 appeared in the fifth season of Supergirl, portrayed by Rath's sister Meaghan Rath.