An organic light-emitting diode comprising: a first electrode; a second electrode disposed opposite to the first electrode; and a first layer interposed between the first electrode and the second electrode, wherein the first layer comprises at least one condensed-cyclic compound represented by Formula 1 below: wherein R 1 to R 11 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, a substituted or unsubstituted C 2 -C 60 heteroaryl group, -N(R 21)(R 22), or - Si(R 23)(R 24)(R 25); L 1 to L 2 are each independently a substituted or unsubstituted C 5 -C 60 arylene group or a substituted or unsubstituted C 2 -C 60 heteroarylene group; a and b are each independently an integer from 0 to 5; and R 21 to R 25 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, or a substituted or unsubstituted C 2 -C 60 heteroaryl group. a first electrode; a second electrode disposed opposite to the first electrode; and a first layer interposed between the first electrode and the second electrode, wherein the first layer comprises at least one condensed-cyclic compound represented by Formula 1 below: wherein R 1 to R 11 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, a substituted or unsubstituted C 2 -C 60 heteroaryl group, -N(R 21)(R 22), or - Si(R 23)(R 24)(R 25); L 1 to L 2 are each independently a substituted or unsubstituted C 5 -C 60 arylene group or a substituted or unsubstituted C 2 -C 60 heteroarylene group; a and b are each independently an integer from 0 to 5; and R 21 to R 25 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, or a substituted or unsubstituted C 2 -C 60 heteroaryl group. wherein R 1 to R 11 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, a substituted or unsubstituted C 2 -C 60 heteroaryl group, -N(R 21)(R 22), or - Si(R 23)(R 24)(R 25); L 1 to L 2 are each independently a substituted or unsubstituted C 5 -C 60 arylene group or a substituted or unsubstituted C 2 -C 60 heteroarylene group; a and b are each independently an integer from 0 to 5; and R 21 to R 25 are each independently a hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a substituted or unsubstituted C 1 -C 60 alkyl group, a substituted or unsubstituted C 2 -C 60 alkenyl group, a substituted or unsubstituted C 2 -C 60 alkynyl group, a substituted or unsubstituted C 1 -C 60 alkoxy group, a substituted or unsubstituted C 3 -C 60 cycloalkyl group, a substituted or unsubstituted C 5 -C 60 aryl group, a substituted or unsubstituted C 5 -C 60 aryloxy group, a substituted or unsubstituted C 5 -C 60 arylthio group, or a substituted or unsubstituted C 2 -C 60 heteroaryl group.