An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, sequentially disposed from an object side. The first lens has negative refractive power, an image side surface thereof is concave, and an angle of view of the optical system including the first lens to the sixth lens is 100° or more. When a focal length of the first lens is f1_1, and a total focal length of the optical system including the first lens to the sixth lens is F1, 1.0