Provided is a heterocyclic compound of Chemical Formula 1: a is a substituted or unsubstituted tetracyclic or higher aromatic or heteroaromatic ring, and b is a benzene or naphthalene ring; at least two of G1 to G3 are a group of Chemical Formula A, and any remaining group, and G101, is hydrogen, deuterium, halogen, cyano, nitro, or a substituted or unsubstituted: silyl, boron, alkyl, alkoxy, cycloalkyl, aryl, or heteroaryl group; L1 and L2 are a direct bond, or a substituted or unsubstituted arylene or heteroarylene group; Ar1 and Ar2 are hydrogen, deuterium, halogen, cyano, nitro, or a substituted or unsubstituted: silyl, boron, alkyl, alkoxy, cycloalkyl, aryl, or a heteroaryl group, or a fused ring group of an aromatic hydrocarbon ring and aliphatic hydrocarbon ring, or bond to each other to form a substituted or unsubstituted heteroring; and an organic light emitting device including the same.