A backlight module including a frame, a light guide plate, a light source and a flexible printed circuit board is provided. The flexible printed circuit board includes a body, a light source carrying portion and a connecting portion. The body is bent, so a top edge and a bottom edge of the body are respectively disposed at a top side and a bottom side of the frame. The light source carrying portion carries the light source. The connecting portion has a first end and a second end. The first end is connected to a middle region of a bottom side of the light source carrying portion. The second end is connected to the bottom edge. The connecting portion is bent, such that the light source carrying portion is disposed on the top side of the frame and the light source is positioned at a side of the light guide plate.