An organic light-emitting device includes a first electrode, a second electrode facing the first electrode, and an organic layer between the first electrode and the second the organic layer including an emission layer. The organic layer includes a first compound represented by Formula 1 and a second compound represented by Formula 2: where R1, to R3, R11 to R13, R21 to R24, X, L1 to L3, L11 to L13, a1 to a3, b1 to b3, c1 to c3, a11 to a13, b11 to b13, and c11 to c13 are as defined in the specification.