An organic light emitting device comprising: an anode; a cathode; and a light emitting layer that is provided between the anode and the cathode, wherein the light emitting layer comprises a compound represented by the following Chemical Formula 1 and a compound represented by the following Chemical Formula 2: wherein in Chemical Formula 1: Y is O or S; X 1, X 2 and X 3 are each independently CH or N, provided that at least one of X 1, X 2 and X 3 is N; and Ar 1 and Ar 2 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; R 1, R 2, and R 3 are each independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; n1 is an integer of 0 to 8; and n2+n3 is an integer of 0 to 6; wherein in Chemical Formula 2: A is a benzene ring fused with two adjacent rings; Ar 3 and Ar 4 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of O and S, provided that at least one of Ar 3 and Ar 4 is substituted with at least one deuterium; each R 4 is independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S, provided that at least one of R 4 is deuterium; and n4 is an integer of 1 to 10. an anode; a cathode; and a light emitting layer that is provided between the anode and the cathode, wherein the light emitting layer comprises a compound represented by the following Chemical Formula 1 and a compound represented by the following Chemical Formula 2: wherein in Chemical Formula 1: Y is O or S; X 1, X 2 and X 3 are each independently CH or N, provided that at least one of X 1, X 2 and X 3 is N; and Ar 1 and Ar 2 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; R 1, R 2, and R 3 are each independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; n1 is an integer of 0 to 8; and n2+n3 is an integer of 0 to 6; wherein in Chemical Formula 2: A is a benzene ring fused with two adjacent rings; Ar 3 and Ar 4 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of O and S, provided that at least one of Ar 3 and Ar 4 is substituted with at least one deuterium; each R 4 is independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S, provided that at least one of R 4 is deuterium; and n4 is an integer of 1 to 10. Y is O or S; X 1, X 2 and X 3 are each independently CH or N, provided that at least one of X 1, X 2 and X 3 is N; and Ar 1 and Ar 2 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; R 1, R 2, and R 3 are each independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S; n1 is an integer of 0 to 8; and n2+n3 is an integer of 0 to 6; wherein in Chemical Formula 2: A is a benzene ring fused with two adjacent rings; Ar 3 and Ar 4 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of O and S, provided that at least one of Ar 3 and Ar 4 is substituted with at least one deuterium; each R 4 is independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S, provided that at least one of R 4 is deuterium; and n4 is an integer of 1 to 10. A is a benzene ring fused with two adjacent rings; Ar 3 and Ar 4 are each independently a substituted or unsubstituted C 6-60 aryl, or a substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of O and S, provided that at least one of Ar 3 and Ar 4 is substituted with at least one deuterium; each R 4 is independently hydrogen, deuterium, substituted or unsubstituted C 6-60 aryl, or substituted or unsubstituted C 2-60 heteroaryl containing at least one heteroatom selected from the group consisting of N, O and S, provided that at least one of R 4 is deuterium; and n4 is an integer of 1 to 10.