One or more embodiments of a backlight assembly include a light guide plate (LGP), a light source module and an optical sheet. The LGP includes a side surface and an upper surface. The light source module includes a power-transmitting member and a plurality of point light sources disposed on the power-transmitting member. A side portion of the power-transmitting member is disposed on a peripheral portion of the upper surface adjacent to the side surface and a light-exiting surface of the point light sources facing the side surface to be adjacent to the side surface. The optical sheet is disposed on the upper surface. A portion of the optical sheet is disposed between a corner portion of the upper surface and the power-transmitting member adjacent to the light-exiting surface. The amount of the light absorbed by a reflective member may be decreased to improve the efficiency of the light.