The present invention addresses a problem of providing a zoom lens which achieves a longer focal length and has a shorter optical overall length at the telephoto end, and an imaging apparatus provided with the zoom lens. In order to solve the problem, a zoom lens is configured to include, in order from the object side, a positive first lens group G1, a negative second lens group G2, a positive composite positive lens group, and a negative composite negative lens group. The composite positive lens group includes a positive third lens group G3, and is consisting of one or more lens groups having positive refractive power. The composite negative lens group includes a negative A lens group and a negative B lens group having negative refractive power. In the zoom lens, changing focal length is performed by varying distances between the lens groups, and a predetermined condition is satisfied.