A zoom lens includes: a master lens including in order from an object side: a positive first lens unit configured not to move for zooming; a negative second lens unit configured to move for zooming; at least one lens unit configured to move for zooming; and a positive relay lens unit arranged closest to the image side; and an extender lens unit configured to change a focal length range of the zoom lens by one of: being inserted in place of a lens unit arranged adjacent to the relay lens unit on the object side; and being inserted into a space adjacent to the positive relay lens unit on the object side, wherein the extender lens unit includes a positive lens Gp, and an Abbe number and a partial dispersion ratio of the positive lens Gp are suitably set.