A semiconductor package according to the present invention includes a substrate; first and second semiconductor chips mounted on a first surface of the substrate; and a heat-radiation sheet. The heat-radiation sheet includes a heat-transferable conductive layer and first and second insulating layers formed on top and bottom surfaces of the heat-transferable conductive layer, respectively. The heat-radiation sheet includes a first portion arranged between the first semiconductor chip and the second semiconductor chip; and a second portion extending at least a side of the first portion. The second portion is connected to the substrate. The second insulating layer of the second portion is formed to expose a part of the heat-transferable conductive layer.