A semiconductor package includes a first structure including a first semiconductor chip comprising a first semiconductor integrated circuit, and a second structure on the first structure. The second structure includes a second semiconductor chip including a second semiconductor integrated circuit, a semiconductor pattern horizontally spaced apart from the second semiconductor chip and on a side surface of the second semiconductor chip, an insulating pattern between the second semiconductor chip and the semiconductor pattern, and through-electrode structures. At least one of the through-electrode structures penetrates through at least a portion of the second semiconductor chip or penetrates through the semiconductor pattern. The semiconductor pattern has a first side surface facing the side surface of the second semiconductor chip and a second side surface opposing the first side surface. The second side surface of the semiconductor pattern is vertically aligned with a side surface of the first semiconductor chip.