A zoom lens suitable for imaging an object on a photosensitive device is provided. The zoom lens includes a first lens group, a second lens group, a third lens group and a fourth lens group, which are arranged in series. The fourth lens group is disposed near the photosensitive device. The second lens group and the third lens group are suitable for moving between the first lens group and the fourth lens group. The first lens group, the second lens group, the third lens group and the fourth lens group include at least a glass lens and a plurality of plastic lenses. The number of the plastic lenses is more than the number of glass lenses. Thus, overall cost of producing the zoom lens is lower.