A semiconductor package includes a package substrate with a first vent hole, a first semiconductor chip mounted the package substrate, an interposer including supporters on a bottom surface of the interposer and a second vent hole, wherein the supporters contact a top surface of the first semiconductor chip, and the interposer is electrically connected to the package substrate through connection terminals. The semiconductor package further include a second semiconductor chip mounted on the interposer, and a molding layer disposed on the package substrate to cover the first semiconductor chip, the interposer, and the second semiconductor chip.