An optical system includes a first lens having negative refractive power and having two concave surfaces, a second lens having positive refractive power, a third lens having refractive power, a fourth lens having refractive power, a fifth lens having refractive power, a sixth lens having refractive power, and a seventh lens having refractive power. The first to seventh lenses are sequentially disposed from an object side. Whereby an aberration improvement effect may be increased and high resolution and a wide angle may be implemented.