Abstract: A lock system for a shed having a crossbar which is inserted through an opening in a side wall of the shed through guides mounted on the rear of the front wall and the doors of the shed and secured by a lock. The crossbar is a solid, elongated rod with a first lock plate projecting from one end of the rod. The guides are made from a plurality of sections of a hollow tube mounted on the rear of the front walls and door of the shed with the bores of each section aligned horizontally and in registry, so that the guides extend for substantially the length of the rod. A stationary bracket is mounted to the interior of the shed with a second lock plate extending through the opening in the side wall of the shed. A base plate having an aperture defined therein is attached to the exterior of the side wall of the shed, the aperture being dimensioned to permit the rod and the first and second lock plates to extend through the aperture.