An organometallic compound of Formula 1: wherein, in Formula 1, M is iridium, platinum, osmium, titanium, zirconium, hafnium, europium, terbium, thulium or rhodium, at least two of ring A to ring D are each, independently from one another, of Formula 2 below, and the rest are each, independently from one another, a substituted or an unsubstituted hydrocarbon ring group having 5 to 60 ring-forming carbon atoms, or a substituted or an unsubstituted heterocyclic group having 1 to 60 ring-forming carbon atoms: wherein, in Formula 2, R 1 and R 2 are each, independently from one another, a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or an unsubstituted oxy group, a substituted or an unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or an unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or an unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or are bonded to an adjacent group to form a ring; is a position bonded to M of the Formula 1; and is a position, independently from one another, bonded to any one of ring A to ring D of the Formula 1, wherein substituted means substituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. M is iridium, platinum, osmium, titanium, zirconium, hafnium, europium, terbium, thulium or rhodium, at least two of ring A to ring D are each, independently from one another, of Formula 2 below, and the rest are each, independently from one another, a substituted or an unsubstituted hydrocarbon ring group having 5 to 60 ring-forming carbon atoms, or a substituted or an unsubstituted heterocyclic group having 1 to 60 ring-forming carbon atoms: wherein, in Formula 2, R 1 and R 2 are each, independently from one another, a hydrogen atom, a deuterium atom, a halogen atom, a cyano group, a substituted or an unsubstituted oxy group, a substituted or an unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or an unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or an unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms, or are bonded to an adjacent group to form a ring; is a position bonded to M of the Formula 1; and is a position, independently from one another, bonded to any one of ring A to ring D of the Formula 1, wherein substituted means substituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group.