A semiconductor package including a chip stack structure, a redistribution layer (RDL) structure and conductive plugs is provided. The chip stack structure includes stacked chips. Each of the chips includes a pad. The pads on the chips are located on the same side of the chip stack structure. The RDL structure is disposed on the first sidewall of the chip stack structure and adjacent to the pads. The conductive plugs penetrate through the RDL structure. The conductive plug is connected to the corresponding pad.