Abstract: A rotatable support assembly which may be easily attached directly to an existing regulation-type mailbox and to an existing ground post for the mailbox. The mailbox is attached to the top surface of an inner sleeve which is telescopically inserted in an outer sleeve. Inwardly projecting from the outer sleeve is a fixed cam follower on which travels an upwardly curved camming slot formed in the wall of the inner sleeve and spanning a horizontal angle of 180.degree.. Thus, the follower and slot are both concealed from view and also are protected from damage by external forces. In the normal mail-receiving position of the mailbox, the upper end of the camming slot rests on the cam follower, and the mailbox points toward the road to facilitate the delivery of mail. A simple spring-loaded lock may be provided to maintain the mailbox in this normal position.