A backlight assembly includes a light guide plate including a light incident face, a light exiting face extended from one end portion of the light incident face, and a reflection face extended from another end portion of the light incident face. The reflection face includes a first reflection face extended from another end portion of the light incident face, and a second reflection face horizontally extended from the first reflection face. The backlight assembly additionally includes a light adsorption member disposed adjacent to the reflection face to prevent the light from reflecting. A reflection plate and optical sheets are disposed adjacent to the light guide plate, so that entire thickness of the backlight assembly is reduced. In addition, leakage of the light incident around the third light exiting face is prevented to improve the quality of the image displayed through the LCD device.