A telephoto zoom lens system includes a first lens group having a positive focal length, a second lens group having a negative focal length, a third lens group having a positive or negative focal length, a fourth lens group having a positive focal length, and a fifth lens group for performing hand shake compensation by allowing a portion of the fifth lens group to move perpendicularly to the optical axis. During zooming, the first and fifth lens groups are fixed and the second, third, and fourth lens groups move, and the third or fourth lens group is a focusing lens group.