Abstract: A self-sizing cap provides a secure, optimum fit upon a wearer's head over a range of sizes. The cap includes a crown and a headband in the form of a plurality of headband segments extending circumferentially along the lower peripheral edge of the crown of the cap. A first headband segment is located along a back portion of the crown and is constructed of a uniaxially resiliently stretchable material oriented for stretching along circumferential directions. A second headband segment is constructed of a substantially non-stretchable material, preferably a perspiration-absorbing material, and is located along a front portion of the crown. Third headband segments are located along side portions of the crown, placed between the first and second headband segments, and are constructed of a biaxially resiliently stretchable material.