A solar cell and a method of fabricating the same are provided according to one or more embodiments. According to an embodiment, the solar cell includes a substrate, a back electrode layer formed on the substrate, a light absorbing layer formed on the back electrode layer, and a transparent electrode layer formed on the light absorbing layer, wherein the light absorbing layer is comprised of copper (Cu), gallium (Ga), indium (In), sulfur (S), and selenium (Se) and includes a first concentration region in which concentrations of sulfur (S) gradually decrease in the light absorbing layer going in a first direction from the back electrode layer to the transparent electrode layer.