A semiconductor package and a method of forming the same are provided. The semiconductor package includes: a semiconductor substrate having a front side and a back side, the semiconductor substrate having a chip area and a dummy area; a front structure below the front side, and including an internal circuit, an internal connection pattern, a guard pattern, and a front insulating structure; a rear protective layer overlapping the chip area and the dummy area, and a rear protrusion pattern on the rear protective layer and overlapping the dummy area, the rear protective layer and the rear protrusion pattern being on the back side; a through-electrode structure penetrating through the chip area and the rear protective layer, and electrically connected to the internal connection pattern; and a rear pad electrically connected to the through-electrode structure. The internal circuit and the internal connection pattern are below the chip area, and the guard pattern is below the chip area adjacent to the dummy area.