A fan-out semiconductor package includes a core member having a through hole, at least one dummy structure disposed in the core member, a semiconductor chip disposed in the through hole and including an active surface on which a connection pad is disposed and an inactive surface opposing the active surface, an encapsulant sealing at least a portion of each of the core member and the semiconductor chip, and filing at least a portion of the through hole, and a connection member disposed on the core member and the active surface of the semiconductor chip, and including a redistribution layer electrically connected to the connection pad.