Provided is a heterocyclic compound of Chemical Formula 1:






wherein X1 is CR1 or N, X2 is CR2 or N, X3 is CR3 or N, X4 is CR4 or N, Y1 is CR5 or N, Y2 is CR6 or N, Y3 is CR7 or N, Y4 is CR8 or N, Z1 is CR9 or N, Z2 is CR10 or N, Z3 is CR11 or N, and Z4 is CR12 or N, wherein X1 to X4, Y1 to Y4 and Z1 to Z4 are not N at the same time; and
at least one of R1 to R12 is Chemical Formula 2:










wherein A1 is O, S or Se; L1 is a direct bond, or a substituted or unsubstituted arylene or heteroarylene group; at least one of Ar1 and Ar2 is a substituted or unsubstituted alkyl group, and the rest is a substituted or unsubstituted aryl or heteroaryl group; and the rest are the same as or different from each other, and each independently is hydrogen, deuterium, halogen, cyano, nitro, hydroxyl, carbonyl, ester, imide, amide, or a substituted or unsubstituted: alkyl, cycloalkyl, alkoxy, aryloxy, alkylthioxy, arylthioxy, alkylsulfoxy, arylsulfoxy, alkenyl, silyl, boron, amine, arylphosphine oxide, aryl, or heteroaryl group; or adjacent groups bond to each other to form a substituted or unsubstituted ring,
and an organic light emitting device comprising the same.