The Courtneys describe their style as "slacker pop" and "artisanal grunge;"critics have categorized them as jangle-pop, garage pop, and surf rock. They are most commonly associated with the Dunedin Sound, particularly Flying Nun artists such as The Clean; they became the first non-New Zealand band to sign with the label after thirty-five years. They cite Eddy Current Suppression Ring, Pavement, Dinosaur Jr., and Fugazi as inspirations, with Teenage Fanclub, Big Star, and Phoenix cited as particular influences on II. Shoegaze has also been cited as an influence, largely due to Courtney Loove's unique open tuning.
Lyrically, the band has been noted for their pop culture references. These include actors ("K.C. Reeves", about Keanu Reeves), movies and television shows (including "Lost Boys" and "90210"), and other musicians (the "mandatory suicide" refrain from "Manion" is a reference to the Slayer song of the same name; "Nu Sundae" is an oblique reference to Calgary band Nü Sensae).