Abstract: A locking letter tray for receiving letters, documents or the like, and for preventing unauthorized access thereto, is characterized by a unitary structure forming an essentially closed compartment having an elongated narrow slot through a side wall thereof and a lockable door, and an open compartment juxtaposed and sharing a common wall therewith. The slot is sufficiently long and wide for the passage of documents therethrough and into the closed compartment, but is narrow enough to prevent hands from entering, and may be equipped with baffles to inhibit removal of documents by dumping, shaking, probing etc. The lockable door precludes unauthorized access to the closed compartment to provide security for documents therein, and the open compartment may advantageously be used for incoming or outgoing nonconfidential mail.