A semiconductor package is provided. The semiconductor package includes a redistribution layer, a semiconductor chip, solder balls, an interposer, an encapsulant layer, and an underfill layer. The semiconductor chip is electrically connected to the redistribution layer, and disposed on an upper surface of the redistribution layer. The solder balls are disposed on the upper surface of the redistribution layer spaced apart from the semiconductor chip and are electrically connected to the redistribution layer. The interposer is electrically connected to the solder balls, and is disposed on an upper surface of the solder balls. The encapsulant layer encapsulates the semiconductor chip and side surfaces of the redistribution layer under the interposer. The underfill layer fills a space between a lower surface of the interposer and an upper surface of the encapsulant layer. The encapsulant layer includes a side surface encapsulant region surrounding the side surfaces of the redistribution layer.