A backlight assembly comprising: a light source which emits light; a light guide plate disposed adjacent to the light source and which receives the light emitted from the light source; a light source supporter consisting of a metal plate for dissipating heat generated by the light source and comprising a bottom plane including a first region and a second region; and a first receiving unit comprising a bottom surface and a side wall, wherein the light source and the light guide plate are disposed on the first region of the bottom plane, the second region extends from a portion of the first region on which the light source is disposed, the bottom surface is disposed opposite the light guide plate, and the side wall is disposed at an end portion of the bottom surface along a direction perpendicular to a plane defined by the bottom surface; wherein a gap is formed on the second region and between the light source and the side wall of the first receiving unit; further comprising a middle frame, wherein at least a portion of the middle frame is disposed in the gap; and wherein the light source supporter comprises a bent portion connected to an elongated end of the second region of the bottom plane and extending substantially perpendicular to the bottom plane from an edge portion of the bottom plane along the side wall of the first receiving unit; wherein the bottom plane contacts the bottom surface; characterized in that the bent portion contacts the side wall ot the first receiving unit; and the middle frame comprises a U-shaped portion, and the U-shaped portion of the middle frame is disposed in the gap; the middle frame further comprises a first portion connected to the U-shaped portion and disposed on an optical sheet disposed on the light source and the light guide plate; and the middle frame further comprises a further portion connected to the U-shaped portion and disposed on the side wall of the first receiving unit and on the bent portion of the light source supporter. a light source which emits light; a light guide plate disposed adjacent to the light source and which receives the light emitted from the light source; a light source supporter consisting of a metal plate for dissipating heat generated by the light source and comprising a bottom plane including a first region and a second region; and a first receiving unit comprising a bottom surface and a side wall, the light source and the light guide plate are disposed on the first region of the bottom plane, the second region extends from a portion of the first region on which the light source is disposed, the bottom surface is disposed opposite the light guide plate, and the side wall is disposed at an end portion of the bottom surface along a direction perpendicular to a plane defined by the bottom surface; wherein a gap is formed on the second region and between the light source and the side wall of the first receiving unit; further comprising a middle frame, wherein at least a portion of the middle frame is disposed in the gap; and wherein the light source supporter comprises a bent portion connected to an elongated end of the second region of the bottom plane and extending substantially perpendicular to the bottom plane from an edge portion of the bottom plane along the side wall of the first receiving unit; wherein the bottom plane contacts the bottom surface; characterized in that the bent portion contacts the side wall ot the first receiving unit; and the middle frame comprises a U-shaped portion, and the U-shaped portion of the middle frame is disposed in the gap; the middle frame further comprises a first portion connected to the U-shaped portion and disposed on an optical sheet disposed on the light source and the light guide plate; and the middle frame further comprises a further portion connected to the U-shaped portion and disposed on the side wall of the first receiving unit and on the bent portion of the light source supporter.