A zoom lens including a first lens group and a second lens group arranged in sequence from a magnified side toward a reduced side is provided. The first lens group has a negative refractive power and includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence from the magnified side toward the reduced side, of which the refractive powers are respectively positive, negative, negative, and positive. The second lens group has a positive refractive power and includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens arranged in sequence from the magnified side toward the reduced side, of which the refractive powers are respectively positive, negative, positive, negative, positive, negative, and positive. The eighth lens, the ninth lens, and the tenth lens together form a triple cemented lens.