A semiconductor package device includes a lower package, an interposer disposed on the lower package and including a ground layer and at least one opening, and an upper package on the interposer. The lower package includes a first package substrate, a first semiconductor chip on the first package substrate, and a first molding compound layer on the first package substrate. The upper package includes a second package substrate and at least one upper semiconductor chip on the second package substrate. A heat transfer member includes a first portion disposed between the interposer and the upper package, a second portion disposed in the at least one opening of the interposer, and a third portion disposed between the interposer and the lower package.