An organic light-emitting device may include: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode, wherein the organic layer may include an emission layer, the emission layer may include a first compound, a second compound, and a fluorescent dopant, the first compound, the second compound, and the fluorescent dopant may be different from one another, the total weight of the first compound and the second compound may be greater than a weight of the fluorescent dopant, and the first compound may be a compound represented by Formula 1: Formula 1 may be understood by referring to the description of Formula 1 provided herein.