The <em>Garcinia</em> genus is a well known tropical plant in the Indo-Malesiana region and mainly distributed in tropical countries including Indonesia, Thailand, and Malaysia. Previous phytochemical studies on <em>Garcinia </em>species have led to the identification and isolation of mainly prenylated xanthones. This research describes the isolation and structure elucidation of isolated triterpenoids compounds from the bark of <em>Garcinia porecta</em>. Dried powder bark of <em>G. porecta </em>was extracted with methanol and then partitioned with <em>n</em>-hexane, ethyl acetate, and <em>n</em>-butanol. The <em>n</em>-hexane extract then was separated and purified with chromatography techniques to obtain isolated compounds <strong>1</strong><strong> </strong>and<strong> 2</strong>. The chemical structure of isolated compounds was elucidated by spectroscopic methods including one and two-dimensional NMR as well as high-resolution mass spectrometric analysis and identified as lanosterol (<strong>1</strong>) dan arabidiol (<strong>2</strong>), respectively. These triterpenoids were isolated from this plant for the first time. Compound <strong>1</strong> and <strong>2</strong> showed weak cytotoxic activity against MCF-7 breast cancer cells with IC₅₀ values of 60.09 dan 46.17 µM, respectively.