A backlight unit including a plurality of light sources configured to emit primary light, and a quantum dot composite. The quantum dot composite includes quantum dot phosphors excited by primary light supplied from the plurality of light sources so as to emit secondary light having a different wavelength than the primary light, and scattering particles that are configured to scatter the primary light. The scattering particles include first scattering particles, and second scattering particles different from the first scattering particles in size and composed of particles each having a diameter in the range of 5 to 50 nm.