Kieran John Callinan (born 21 January 1986), known by his stage name Kirin J. Callinan, is an Australian singer, songwriter, and guitarist. He is also a founding member of Mercy Arms and has played with the Night Game, Jack Ladder and the Dreamlanders, Mark Ronson and Genesis Owusu.

Referred to as the enfant terrible of Australia's underground rock music scene, Callinan is known for his flamboyant public persona, confrontational live shows, and diverse musical output in which, according to Spin, "the distinctions between talent, irony, and genuine bad taste bleed together until they're indistinguishable." Callinan said that his primary motivation as a musician is to "excite and confuse, ... But you can't do that for any length of time without having sincerity."

Callinan has collaborated with a wide range of musicians, including Mark Ronson, Jimmy Barnes, James Chance, Alex Cameron, Connan Mockasin, Caroline Polachek, Weyes Blood, Pond, Mac Demarco, Ariel Pink, Hubert Lenoir, Julian Casablancas, Genesis Owusu, whistler Molly Lewis and brothers Neil and Tim Finn. Barnes, Cameron and Lewis feature in Callinan's 2017 single "Big Enough"; Barnes' distinctive screaming cameo became an internet meme.