The invention provides a semiconductor package assembly. The semiconductor package assembly includes a first semiconductor package including a first redistribution layer (RDL) structure having a first surface and a second surface opposite to the first substrate. The first RDL structure includes a plurality of first conductive traces close to the first surface of the first RDL structure. An antenna pattern is disposed close to the second surface of the first RDL structure. A first semiconductor die is disposed on the first surface of the first RDL structure and electrically coupled to the first RDL structure. A plurality of conductive structures is disposed on the first surface of the first RDL structure and electrically coupled to the first RDL structure. The plurality of conductive structures is spaced apart from the antenna pattern through the plurality of first conductive traces of the first RDL structure.