A semiconductor package including an organic interposer includes: the organic interposer including insulating layers and wiring layers formed on the insulating layers; a stiffener disposed on the interposer and having a through-hole; a first semiconductor chip disposed in the organic through-hole on the organic interposer; a second semiconductor chips disposed adjacent to the first semiconductor chip in the through-hole on the organic interposer; and an underfill resin filling at least portions of the through-hole and fixing the first semiconductor chip and the second semiconductor chip, wherein the connection pads of the first semiconductor chip and the second semiconductor chip are electrically connected to each other through the wiring layers of the organic interposer.