A zoom lens system capable of correcting a secondary spectrum is disclosed. The zoom lens system includes a first lens unit with a positive optical power, a second lens unit with a negative optical power, an aperture stop, and a rear lens component including at least one lens unit in an order from an object side to an image side. In the zoom lens system, during zooming from a wide angle end to a telephoto end, an interval between the first lens unit and the second lens unit increases, and an interval between the second lens unit and the aperture stop decreases. Then, a material satisfying the following conditions: .nu.d1n<35 .theta.gF1n <-0.0027.nu.d1n+0.680 is used for the negative lens in the first lens unit. Herein, .nu.d1n represents an Abbe number, and .theta.gF1n represents a partial dispersion ratio.