A semiconductor package includes a lower package including a lower substrate, a lower semiconductor chip, and a lower molding layer exposing an upper surface of the lower semiconductor chip, bumps on the lower substrate, the bumps being spaced apart from the lower semiconductor chip, a lead frame on the lower semiconductor chip and on the bumps, the lead frame being electrically connected to the bumps and having a thermal conductivity of about 100 W/mk to about 10,000 W/mk, and an upper package on the lead frame and electrically connected to the lead frame.