A stacked structure of semiconductor packages includes an upper semiconductor package, a lower semiconductor package and inter-package connectors. The upper semiconductor package includes an upper package substrate, a plurality of upper semiconductor chips stacked on the upper package substrate, and conductive upper connection lands formed on a bottom surface of the upper package substrate. The lower semiconductor package includes a lower package substrate, a plurality of lower semiconductor chips stacked on the lower package substrate, and lower through-silicon vias vertically penetrating the lower semiconductor chips. The inter-package connectors may electrically connect the through-silicon vias to the upper connection lands.