An optical imaging system includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens having a negative refractive power, and a fifth lens having a positive refractive power. The first to fifth lenses are sequentially disposed from an object side to an imaging plane. One or more lenses among the first to fifth lenses are formed using a glass material.