Three new oxygenated sesquiterpenoids, gibberodione (1), peroxygibberol (2), and sinugibberodiol (3), along with sarcophytol L (4) were isolated from a Formosan soft coral, Sinularia gibberosa. The structures of the new metabolites were determined on the basis of extensive spectroscopic analyses and by comparison of NMR data with those of related metabolites. Metabolites 2 and 4 were found to exhibit moderate cytotoxicity toward a human liver carcinoma cell line.