A zoom lens includes, in order from an object side to an image side, a first lens unit of a negative refractive power, a second lens unit of a positive refractive power, and a third lens unit of a positive refractive power, each lens unit being moved during zooming, wherein the second lens unit includes two positive lenses, a negative lens, a positive lens in order from the object side to the image side, and an average refractive index Nd2p for d-line of materials of the positive lenses in the second lens unit and a refractive index Nd2n for d-line of a material of the negative lens in the second lens unit are appropriately set.