A semiconductor package includes a redistribution substrate having first and second surfaces, and an insulating member and a plurality of redistribution layers on different levels in the insulating member and electrically connected together; a plurality of under bump metallurgy (UBM) pads in the insulating member and connected to a redistribution layer, among the plurality of redistribution layers, adjacent to the first surface, the UBM pads having a lower surface exposed to the first surface of the redistribution substrate; a dummy pattern between the UBM pads in the insulating member, the dummy pattern having a lower surface located at a level higher than the lower surface of the UBM pads; and at least one semiconductor chip on the second surface of the redistribution substrate and having a plurality of contact pads electrically connected to a redistribution layer, among the plurality of redistribution layers, adjacent to the second surface.