Abstract: An adjustable-length closet fastener (1) has a fastener shank (2, 32) with an anchor-ridge head (3, 33) which is sized and shaped for positioning side walls of the anchor-ridge head against walls (5) of a predetermined retainer cavity (6) to arrest rotation of the fastener shank and which is sized and shaped for positioning a fastener shank-side surface (9) of the anchor-ridge head against a ceiling (10) of the predetermined retainer cavity at opposite sides of a shaft orifice in the predetermined retainer cavity to prevent exit of the adjustable-length closet fastener from the predetermined retainer cavity. A length-adjustment sleeve (11) with internal machine threads (12) is attached to the fastener shank for extension a predetermined distance towards a predetermined fastening position (13). A length-adjustment bolt (16) with external machine threads (17) that match the internal machine threads of the length-adjustment sleeve is screwed a desired length-adjustment distance into the length-adjustment sleeve.