Disclosed are semiconductor packages and methods of fabricating the same. The semiconductor package includes a redistribution substrate including redistribution line patterns in a dielectric layer, and a semiconductor chip on the redistribution substrate. The semiconductor chip includes chip pads electrically connected to the redistribution line patterns. Each of the redistribution line patterns has a substantially planar top surface and a nonplanar bottom surface. Each of the redistribution line patterns includes a central portion and edge portions on opposite sides of the central portion. Each of the redistribution line patterns has a first thickness as a minimum thickness at the central portion and a second thickness as a maximum thickness at the edge portions.