A light scanning system and an image forming apparatus including the same, the light scanning system including: one or more light sources to emit light; a deflector to deflect the emitted light; and one or more f-θ lenses to focus the deflected light onto a photosensitive medium, wherein the light emitted by the one or more light sources is obliquely incident on a plane perpendicular to a rotational axis of the deflector, and the f-θ lens satisfies −0.5