An exemplary backlight module (5) includes a light guide plate (54) having a light incident surface (546), and a circuit board (62) disposed adjacent to the light incident surface. A pair of protrusions (544) of the light guide plate engages in a pair of fixing holes (524) of the circuit board, thereby fixing the circuit board and the light guide plate together. The backlight module may further include one or more optical films. In such case, the above-described fixing means may further include a plurality of side-blocks or a plurality of corner-blocks integrally formed on a light emitting surface of the light guide plate. The side-blocks or corner-blocks enable the optical films to be tightly held on the light guide plate without gaps therebetween.