A fingerprint sensor includes: a light sensing layer including a light sensing element, wherein a sensing current flows in the light sensing element according to incident light; and a collimator layer disposed on the light sensing layer and including a light guide unit guiding light to the light sensing element. The light guide unit includes: a light-transmitting unit configured to provide light to the light sensing element; and a first light-blocking unit disposed on an inner surface of the light-transmitting unit.