Breast cancer is a cancer that is hard to treat. The concept of this study is treated using β-sitosterol and derivatives, including 3β-galactose sitosterol, Sitostenone, 3β-glucose sitosterol, Poriferasta-5,22E,25- trien-3β-ol,22- dehydrocholesterol. The testing procedure carried out on MCF7 and MDA-MB-231 breast cancer cells, as well as MCF 10A non-cancerous breast epithelial cells. The compounds with the highest and lowest cytotoxicity to cancer and non-cancer cells were analyzed to this study. The most qualified is 3β-glucose, reported IC₅₀ values against MCF7 and MDA-MB-231 cells of 265 µg/ml and 393.862 µg/ml, respectively. Meanwhile, the IC₅₀ value against MCF 10A cells was 806.833 µg/ml and the morphological changes manifested signs of apoptotic. The results of molecular docking showed that 3β-galactose sitosterol reported antiproliferation interactions with binding energy of estrogen receptor beta (3OLL) were -3.31 kcal/mol, and caspase-3 (2XYG) were -6.38 μM. The mRNA expression confirmed the occurrence of apoptosis with caspase-9 and 3, as well as upregulated PR-AB and ESR2 progesterone and estrogen receptor beta gene. Mechanism used by 3β-glucose sitosterol to induce apoptosis and target tumor cell types, that is predict the compound served as adjuvant therapy to enhance the success rate of treatment.