An optical imaging system includes: a first lens having refractive power, a second lens having refractive power, a third lens having refractive power, a fourth lens having refractive power, and a fifth lens having refractive power. Here, the first lens, the third lens, and the fifth lens may have refractive indices of about 1.6 or more, and an entire field of view of the optical imaging system may be about 120° or more.