A zoom lens includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, and a fifth lens unit having a positive refractive power. The first to fifth lens units are arranged in order from the object side to the image side. All of the lens units are moved during zooming from the wide-angle end to the telephoto end such that the distance between the first lens unit and the second lens unit is increased and the distance between the third lens unit and the fifth lens unit is increased. The refractive power of the fourth lens unit and the refractive power of the fifth lens unit are adequately set with respect to the zoom ratio.