Thespesia populnea grows as a small tree or large shrub that occurs throughout Polynesia. We report the isolation of 7-hydroxycadalene (6), thespesenone (7), and dehydrooxoperezinone-6-methyl ether (8) from its red heartwood. Compounds 7 and 8 are reported for the first time in nature. Several other sesquiterpene quinones were isolated including mansonone E (4), mansonone F (3), mansonone D (1), mansonone G (9), mansonone M (10), and thespesone (4); the (13)C NMR spectra of these compounds are reported for the first time.