A semiconductor device includes a first package, and a second package stacked on the first package. Each of the first and second packages includes a first redistribution substrate having a first redistribution pattern, a first semiconductor chip on the first redistribution substrate and connected to the first redistribution pattern, a first molding layer covering the first semiconductor chip on the first redistribution substrate, a first through-electrode penetrating the first molding layer so as to be connected to the first redistribution pattern, and a second through-electrode penetrating the first molding layer and not connected to the first redistribution pattern. The first redistribution pattern of the second package is electrically connected to the second through-electrode of the first package.