A semiconductor package includes a base structure having a base pad, a first semiconductor chip on the base structure, and having a first connection pad bonded to the base pad, a first bonding structure including an base insulation layer of a base structure and a first lower insulation layer of the first semiconductor chip bonded to the base insulation layer, a second semiconductor chip on the first semiconductor chip, and having a second connection pad connected to the first through-electrode, and a second bonding structure including a first upper insulation layer of the first semiconductor chip, and a second lower insulation layer of the second semiconductor chip bonded to the first upper insulation layer, and the first upper insulation layer has a dummy insulation portion extending onto the base structure around the first semiconductor chip.