A semiconductor package includes a substrate, a rewiring layer, a plurality of semiconductor chip stack structures, and a second semiconductor chip. The rewiring layer is disposed on an upper surface of the substrate. The rewiring layer includes a concave portion. The semiconductor chip stack structures include a plurality of first semiconductor chips. The first semiconductor chips are disposed on the rewiring layer. The first semiconductor chips are spaced apart from each other in a horizontal direction. The second semiconductor chip is disposed within the concave portion. The second semiconductor chip is configured to electrically connect each of the plurality of semiconductor chip stack structures to each other.