All-reflective telescopes have found significant utilization in the astronomical community, government, and industry. Until recently, the concept of an all-reflective zoom telescope, particularly having an unobscured pupil, with meaningful capabilities was unknown. Several designs of unobscured-pupil zoom telescopes comprising only three mirrors are presented. The designs discussed have fields-of-view up to 3 degrees by 3 degrees, F/#s as low as 3 and zoom ratios of up to 4:1. The rms geometric blur diameter for one zoom telescope, having a 4:1 zooming range, was found to be 45 (mu) radians in the wide FOV condition (2 degrees by 2 degrees and F/4).