Provided is an organic light-emitting device including a plurality of pixels, each including a first sub-pixel, a second sub-pixel, and a third sub-pixel having different colors from each other. Each of the pixels includes a substrate, a first electrode layer on the substrate, a first light-emitting layer disposed on the first electrode in the first, second and third sub-pixels, an auxiliary layer disposed on the first light-emitting layer in the second and third sub-pixels, a second light-emitting layer disposed on the auxiliary layer in the second sub-pixel, a third light-emitting layer disposed on the auxiliary layer in the third sub-pixel, and a second electrode layer on the first, second, and third light-emitting layers.