A heterocyclic compound represented by the following Formula 1: wherein, in Formula 1, Z 1 to Z 3 are each independently CR 1 or N, at least one of Z 1 to Z 3 is N, R 1 is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, wherein the alkyl may be linear, branched, or cyclic, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, Ar 1 to Ar 3 are each independently a group represented by the following Formula 2, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and at least two of Ar 1 to Ar 3 are groups represented by Formula 2: in Formula 2, X 1 is O or S, "n" is an integer of 1 to 3, "a" to "c" are each independently an integer of 0 to 4, "d" is an integer of 0 to 2, and R 2 to R 5 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, wherein the alkyl may be linear, branched, or cyclic, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, at least one of the carbazole moieties in Formula 2 is bonded in an ortho relationship with respect to the nitrogen-containing monocycle of Formula 1. Z 1 to Z 3 are each independently CR 1 or N, at least one of Z 1 to Z 3 is N, R 1 is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, wherein the alkyl may be linear, branched, or cyclic, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, Ar 1 to Ar 3 are each independently a group represented by the following Formula 2, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, and at least two of Ar 1 to Ar 3 are groups represented by Formula 2: in Formula 2, X 1 is O or S, "n" is an integer of 1 to 3, "a" to "c" are each independently an integer of 0 to 4, "d" is an integer of 0 to 2, and R 2 to R 5 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, wherein the alkyl may be linear, branched, or cyclic, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, at least one of the carbazole moieties in Formula 2 is bonded in an ortho relationship with respect to the nitrogen-containing monocycle of Formula 1. X 1 is O or S, "n" is an integer of 1 to 3, "a" to "c" are each independently an integer of 0 to 4, "d" is an integer of 0 to 2, and R 2 to R 5 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, wherein the alkyl may be linear, branched, or cyclic, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms, at least one of the carbazole moieties in Formula 2 is bonded in an ortho relationship with respect to the nitrogen-containing monocycle of Formula 1. <EOS>