A backlight assembly (400; 400A; 400B; 400C; 400D) comprising: a first light guide plate; a second light guide plate spaced apart from the first light guide plate; a light source part disposed between the first light guide plate and the second light guide plate, and including a first light source facing a side of the first light guide plate and a second light source facing a side of the second light guide plate; and a cover part diffusing light irradiated from the light source part and disposed over the light source part, and overlapping with a portion of the first light guide plate and a portion of the second light guide plate the first light guide plate includes a first portion having a first thickness, and a second portion including an inclined portion having an inclined surface and a thickness gradually decreasing towards the first light source, and the second light guide plate includes a first portion having the first thickness, and a second portion including an inclined portion having an inclined surface and a thickness gradually decreasing towards the second light source, wherein the cover part is received in a recess portion defined by the second portion of the first light guide plate and the second portion of the second light guide plate, and the backlight assembly (400; 400A; 400B; 400C; 400D) further comprises a printed sheet (440; 441; 442; 443; 450) reflecting and absorbing light from the light source part and including printed patterns (P1, P2) these on, the printed sheet (440; 441; 442; 443; 450) being either disposed between the light source part and the cover part or disposed above the cover part. a first light guide plate; a second light guide plate spaced apart from the first light guide plate; a light source part disposed between the first light guide plate and the second light guide plate, and including a first light source facing a side of the first light guide plate and a second light source facing a side of the second light guide plate; and a cover part diffusing light irradiated from the light source part and disposed over the light source part, and overlapping with a portion of the first light guide plate and a portion of the second light guide plate the first light guide plate includes a first portion having a first thickness, and a second portion including an inclined portion having an inclined surface and a thickness gradually decreasing towards the first light source, and the second light guide plate includes a first portion having the first thickness, and a second portion including an inclined portion having an inclined surface and a thickness gradually decreasing towards the second light source, wherein the cover part is received in a recess portion defined by the second portion of the first light guide plate and the second portion of the second light guide plate, and the backlight assembly (400; 400A; 400B; 400C; 400D) further comprises a printed sheet (440; 441; 442; 443; 450) reflecting and absorbing light from the light source part and including printed patterns (P1, P2) these on, the printed sheet (440; 441; 442; 443; 450) being either disposed between the light source part and the cover part or disposed above the cover part.