A solar cell is discussed. The solar cell includes a semiconductor substrate of a first conductive type, an emitter region of a second conductive type opposite the first conductive type, which is positioned at a front surface of the semiconductor substrate, a front passivation part positioned on a front surface of the emitter region, a front electrode part which passes through the front passivation part and is electrically connected to the emitter region, a back passivation part positioned on a back surface of the semiconductor substrate, and a back electrode part which passes through the back passivation part and is electrically connected to the semiconductor substrate. The front passivation part and the back passivation part each include a silicon oxide layer. One of the front passivation part and the back passivation part includes an aluminum oxide layer.