The chiral nonanuclear Tb(III) clusters [Tb-9(sal-(R)-Bt)(16)(mu-OH)(10)]+[NO3]-(Tb-(R)-Bt: sal-(R)-Bt=(R)-2-butyl salicylate) and [Tb9 (sal-(S)-Bt)(16)(mu-OH)(10)](+)[NO3](-)(Tb-(S)-Bt: sal-(S)-Bt=(S)-2-butyl salicylate) were found to exhibit a unique magneto-optical property: the Faraday effect. The clusters were composed of 9 Tb(III) ions bridged by 10 mu-OHs and 16 chiral salicylic acid esters. The Faraday rotation angle of Tb-(R)-Bt was greater than that of Tb-(S)-Bt, indicating that the Faraday effect was affected by the chirality of the Tb(III) clusters. The chiroptical properties of the Tb(III) clusters were estimated using circular dichroism and circularly polarized luminescence. In this study, a new finding concerning chiral magneto-optical properties was investigated.