A semiconductor package includes a first semiconductor die, a first under-fill layer on an upper surface of the first semiconductor die, a second under-fill layer on the first under-fill layer, a second semiconductor die provided on the second under-fill layer, and a mold layer on side surfaces of the second semiconductor die, the second under-fill layer, and the upper surface of the first semiconductor die. The first semiconductor die includes a first substrate, a first redistribution pattern on the first substrate, a first redistribution dielectric layer provided on the first redistribution pattern, and a first dam on the first redistribution dielectric layer and along an edge of the first substrate, and the first under-fill layer contacts a side surface of the first dam.