A semiconductor package system includes a substrate, a first and a second semiconductor package, a first thermal conductive layer, a first passive device, and a heat radiation structure. The first and second semiconductor package and first passive device may be mounted on a top surface of the substrate. The first semiconductor package may include a first semiconductor chip that includes a plurality of logic circuits. The first thermal conductive layer may be on the first semiconductor package. The heat radiation structure may be on the first thermal conductive layer, the second semiconductor package, and the first passive device. The heat radiation structure may include a first bottom surface physically contacting the first thermal conductive layer, and a second bottom surface at a higher level than that of the first bottom surface. The second bottom surface may be on the second semiconductor package and/or the first passive device.