A method of attaching a polarizer includes preparing a first stage on which a display panel is disposed and a second stage on which a first polarizer is disposed, measuring a shape of a curl of the first polarizer; determining an attachment direction of the first polarizer with respect to the display panel based on the measured curl shape of the first polarizer and attaching the first polarizer to a first surface of the display panel by rotating at least one of the first stage and the second stage based on the determined attachment direction.