A zoom lens includes, in order from an object side to an image side, a first lens group of negative refracting power, a second lens group of positive refracting power and a third lens group of positive refracting power, wherein the first and second lens groups are configured to move during a zooming operation, and wherein a focal length of the whole system at a wide-angle end, a focal length of the whole system at a telephoto end, focal lengths of the first, second, and third lens groups, the lateral magnification of the second lens group at the wide-angle end, and the lateral magnification of the second lens group at the telephoto end are appropriately set to assure a zoom lens which is small in the lens whole system size and which provides good optical performance throughout the whole zoom range.