An organic light-emitting device may include: an anode; a cathode; an organic layer located between the anode and the cathode and including an emission layer; an electron blocking layer located between the anode and the emission layer and in direct contact with the emission layer; and a hole blocking layer located between the cathode and the emission layer and in direct contact with the emission layer. The emission layer may include a host and a dopant, the electron blocking layer may be an electron blocking material, the hole blocking layer may include a hole blocking material, and the host, the dopant, the electron blocking material, and the hole blocking material may each satisfy Equations 1-1 to 1-4: T1(EB)≥T1(H)  Equation 1-1 T1(EB)≥T1(D)  Equation 1-2 T1(HB)>T1(H)  Equation 1-3 T1(HB)>T1(D).  Equation 1-4