A semiconductor package includes a package substrate, a semiconductor device, an antenna substrate and a package body. The semiconductor device is disposed on an upper surface of the package substrate. The antenna substrate is disposed on the semiconductor device and includes a core layer, a grounding layer formed on a lower surface of the core layer, and an antenna layer formed on an upper surface of the core layer and electrically connected to the grounding layer through a conductive via of the core layer. The package body encapsulates the semiconductor device and the antenna substrate.