This tailgate security enclosure is a simple, one-piece hinged design that creates a lockable storage area completely protected on all sides. The patented design works in conjunction with the lockable vehicle tailgate and the existing vehicle geometry to secure the area created without the need for a rigid panel connection, any releasable lock mechanisms or other unnecessary hardware. The innovative design eliminates the burden of having to bolt a bunch of panels together. The enclosure maintains the use and function of the rear seat. Quickly and easily installs using standard hand tools in conjunction with an OEM hardtop or soft-top. The assembly removes easily to allow for storage of larger items. On Jeep Wrangler TJ vehicles, the rear tailgate lock must be locked manually with the Jeep key in order for the Tuffy enclosure to function as a secure storage device.