A semiconductor package includes a chip stack comprising semiconductor chips vertically stacked on a substrate in a first direction perpendicular to a top surface of the substrate, pillars between the substrate and the chip stack, an adhesive layer on a bottom surface of a lowermost semiconductor chip of the semiconductor chips, a first lower protective layer between the adhesive layer and the pillars, a second lower protective layer between the first lower protective layer and the adhesive layer, and a mold layer covering the chip stack and filling a space between the pillars. A thickness of the second lower protective layer in the first direction is greater than a thickness of the adhesive layer in the first direction.