The present invention discloses an organic light-emitting device. The organic light-emitting device includes an emission layer including a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises an emission layer, the emission layer comprises a first compound, a second compound, and a third compound, and the first compound and the second compound are different from each other, each of the first compound and the second compound emits light, the third compound does notemit light, and the first compound and the second compound satisfy Conditions and Inequalities as described herein.