Burton "Gus" Guster is a fictional character on the USA Network television comedy Psych and the sequel film series of the same name played by American actor Dulé Hill.

He functions as the "straight man" for Shawn Spencer's antics, and provides sobering advice, helpful knowledge, steady support, and friendship.

Gus is often shown to be academically advanced and knowledgeable on various things, particularly math and science; his experience with pharmaceutical sales aids Shawn in his investigations frequently.

[5] Despite both Shawn and Gus coming to rational conclusions from observable evidence, both occasionally indulge in supernatural explanations for crimes.

In terms of his "nerd" identity, Gus demonstrates extensive knowledge on a wide variety of subjects and studies, as well as adhering to grammatical rules and showing interest in nerdy media.