Semiconductor packages and methods of forming the same are provided. One of the semiconductor package includes a first die, a dummy die, a first redistribution layer structure, an insulating layer and an insulating layer. The dummy die is disposed aside the first die. The first redistribution layer structure is electrically connected to the first die and having connectors thereover. The insulating layer is disposed over the first die and the dummy die and opposite to the first redistribution layer structure. The insulating layer penetrates through the insulating layer.