GIR is the insane, hyperactive robotic assistant of Zim and the closest thing the incompetent Irken has to a friend, having been constructed from scrap parts and given to Zim by the Almighty Tallest just before it was handed to Zim, instead of a regular SIR (Standard-issue Information Retrieval Unit).

GIR is voiced by Rosearik Rikki Simons, and played a main role in three episodes: "Invasion of the Idiot Dog Brain", "My Ventriloquist Blik" and "To Save a Blik", and played minor or secondary roles in almost all other episodes. He was voiced by Wasabi Mizuta in the Japanese dub and Irwin Daayán in the Spanish dub.