A backlight assembly includes a circuit substrate, a light source arranged on the circuit substrate, a light guide plate having a first surface configured to receive light emitted from the light source and a second and different surface to emit light, a wavelength converting unit arranged between the light source and the light guide plate and a spacer arranged around the light source. The spacer is spaced apart from the light source in a direction perpendicular to the light-emitting direction of the light emitted from the light source.