A zoom lens system comprising: a positive first lens unit; a negative second lens unit; a positive third lens unit; and one or more subsequent lens units, wherein in zooming, the first to third lens units are moved along an optical axis to perform magnification change, a lens unit α which is one of the subsequent lens units does not move during zooming, but moves during transition from an imaging state to an accommodated state, and the conditions: 0.8 9.0 (LT: overall length of lens system at a telephoto limit, Dα: axial air-equivalent length between a most image side surface of the lens unit α and an image surface, fGα: focal length of the lens unit α, fW and fT: focal lengths of the entire system at a wide-angle limit and a telephoto limit) are satisfied.