An optical imaging system includes: a first lens group including a plurality of lenses; a second lens group including a plurality of lenses; a first reflecting member disposed on an object side of the first lens group; and a plurality of second reflecting members arranged between the second lens group and an image sensor. One or both of the first lens group and the second lens group is movable along an optical axis, an interval along the optical axis between the first lens group and the second lens group is varied between a first interval and a second interval smaller than the first interval, and as at least one of the first lens group and the second lens group is moved, one or more of the second reflecting members are moved.