A backlight assembly includes a light source assembly including a plurality of light source blocks arranged in a first direction, each light source block including a substrate including a reflecting surface and a plurality of point light sources arranged on the substrate, a lower housing accommodating the light source assembly, and a substrate fixing portion disposed at a boundary between adjacent substrates and fixing the light source assembly to the lower housing. The substrate fixing portion includes a head extending overlapping the boundary between the adjacent substrates of the light source blocks and pressing the substrates towards the lower housing, and an engaging protrusion protruding from the head and fixed to the lower housing.