An organic light emitting device includes a first light-emitting layer between an anode and a cathode, the first light-emitting layer including a first light-emitting part and a second light-emitting part, a second light-emitting layer spaced apart from the first light-emitting layer and including a third light-emitting part and a fourth light-emitting part, the third light-emitting part overlapping the first light-emitting part and not overlapping the second light-emitting part, and the fourth light-emitting part not overlapping either of the first light-emitting part and the second light-emitting part, an intermediate layer between the first light-emitting layer and the second light-emitting layer, a hole transport region to inject/transport a hole into the first light-emitting part, the second light-emitting part, and the fourth light-emitting part, and an electron transport region to inject/transport an electron into the second light-emitting part, the third light-emitting part, and the fourth light-emitting part.