An organic light emitting device comprising an anode; a cathode; and a light emitting layer between the anode and the cathode, the light emitting layer comprising a first compound of Chemical Formula 1 and a second compound of Chemical Formula 2:




wherein: Ar1 and Ar2 are each independently a substituted or unsubstituted C6-60 aryl; R is deuterium or a substituted or unsubstituted C6-60 aryl or C2-60 heteroaryl containing at least one of N, O and S, provided that carbazolyl and benzocarbazolyl are excluded from R; X is O or S; R1 and R10 are each independently hydrogen, deuterium, or a substituent of Chemical Formula 3, provided that one of R1 to R10 is a substituent of Chemical Formula 3:




and the other substituents are as defined in the specification, the device exhibiting improved driving voltage, luminous efficiency and lifetime.