A solar cell can include a front passivation region including a plurality of layers formed of different materials from each other and including a first aluminum oxide layer and a first silicon nitride layer, and a back passivation region including a plurality of layers formed of different materials from each other and including a second aluminum oxide layer and a second silicon nitride layer, wherein a thickness of a first silicon nitride layer is greater than a thickness of the first aluminum oxide layer, and a thickness of a second silicon nitride layer is greater than a thickness of the second aluminum oxide layer.