A zoom lens performs zooming by moving a plurality of lens units, and includes a front lens unit disposed on an object side of an aperture stop and at least one diffractive optical part having positive power, and a rear lens unit disposed on an image side of the aperture stop including at least one refractive optical element made of a solid material and having a positive refractive power. When .nu.d and .theta.gF are the Abbe number and the partial dispersion ratio, respectively, of the material of the refractive optical element, and fD and fN are the focal lengths of the diffractive optical part and the refractive optical element, respectively, in air, the following expressions are satisfied: 0.755<.theta.gF-(-1.665.times.10.sup.-7.nu.d.sup.3+5.213.times.10.sup.- -5.nu.d.sup.2-5.656.times.10.sup.-3.nu.d)<1.011, and 80