Deployable reflectors and antennas and spacecraft using such reflectors are disclosed. An example disclosed reflector includes: a hub having a cross-section formed in a circular, elliptical or polygonal shape; a plurality of ribs, each rib having an inner side surface facing an outer peripheral side of the hub when folded, and an outer side surface that is a surface opposite to the inner side surface, the plurality of ribs being folded to be wound around an outer periphery of the hub such that the inner side surface of each rib and the outer side surface of its adjacent rib partially face each other or the outer side surface of each rib and the inner side surface of its adjacent rib partially face each other, each rib being deployed in a parabolic shape; and a sheet installed across each of the plurality of ribs and capable of reflecting radio waves.