An organic light-emitting device includes a substrate; a first electrode layer and a second electrode layer on the substrate, in parallel to the substrate, and facing each other; an emission layer between the first electrode layer and the second electrode layer, where the emission layer includes a first emission region, a second emission region, and a third emission region, where the emission layer includes a first common emission layer in the first emission region, the second emission region, and the third emission region; a second emission layer in the second emission region between the first common emission layer and the second electrode layer; and a third emission layer in the third emission region between the first common emission layer and the second electrode layer, and where the first common emission layer includes a first host, a first dopant, and a p-type dopant.