The n-hexane fraction from the stem bark of Lansium domesticum Corr. Cv. Kokosan afforded 3 sesquiterpenoids, namely eudesm-4(15),7-dien-1β-ol (1), eudesm-4(15)-ene-1β,6α-diol (2), and octahydro-4-hydroxy-3a-methyl-7-methylene-a-(1-methylethyl)-1H-indene-1-methanol (3). These three compounds were discovered in the Lansium genus for the first time. Their chemical structures were determined based on data generated from various spectroscopic methods, including one- and two-dimensional NMR, as well as mass spectroscopy. Sesquiterpenoid compounds (1-3) have also been evaluated on MCF-7 breast cancer cell lines and the compound 1 showed the strongest activity with an IC50 value of 17.97 µg/mL while compounds 2 and 3 showed moderate and weak activity with IC50 values of 121.65 and 201.57 µg/mL, respectively. The implication of the findings of these compounds is as an illustration that one of these sesquiterpenoids has potential as an anticancer with the presence of double bond which played important role in the cytotoxic activity that can be studied for new drug discovery.