A rotor for an electric motor may include a rotor core having a hole; a magnet inserted in the hole; and a sheet disposed between an inner surface of the hole and a side surface of the magnet, wherein the side surface faces the inner surface. The sheet may include a first contact layer contacting the inner surface of the hole; a second contact layer contacting the side surface of the magnet; and a body layer including a porous structure and disposed between the first contact layer and the second contact layer. The body layer may have a higher porosity than at least one of the first contact layer and the second contact layer.