Breast cancer remains the most prevalent malignancy among women worldwide, with increasing incidence and mortality despite advances in diagnosis and therapy. The development of chemopreventive strategies using phytochemicals offers a promising complementary approach to conventional treatment. Ocimum sanctum Linn. (Tulsi), a revered medicinal plant in Ayurvedic medicine, possesses a diverse array of bioactive compounds such as eugenol, ursolic acid, rosmarinic acid, and apigenin, which have demonstrated potent anticancer properties. Objective:This review aims to critically evaluate current evidence on the chemopreventive potential of O. sanctum in breast cancer, focusing specifically on its ability to induce apoptosis and inhibit metastatic progression through modulation of key molecular pathways. Methods:Published studies from scientific databases including PubMed, Scopus, and ScienceDirect were analyzed, emphasizing in vitro, in vivo, and mechanistic investigations addressing Tulsi’s effects on apoptotic signaling and metastatic suppression in breast cancer models. Results:Evidence indicates that O. sanctum and its phytoconstituents induce apoptosis in breast cancer cells via modulation of the p53 and Bax/Bcl-2 axis, activation of caspase cascades, and inhibition of the PI3K/Akt and NF-κB pathways. Moreover, Tulsi demonstrates anti-metastatic and anti-angiogenic properties by downregulating matrix metalloproteinases (MMP-2, MMP-9), vascular endothelial growth factor (VEGF), and epithelial–mesenchymal transition markers. These molecular modulations collectively suppress tumor proliferation, invasion, and vascularization. Conclusion:The cumulative evidence underscores Ocimum sanctum as a promising phytotherapeutic candidate for breast cancer chemoprevention through its pro-apoptotic and anti-metastatic actions. However, the absence of robust clinical trials, limited pharmacokinetic data, and variability in extract standardization necessitate further translational and clinical research to validate its efficacy and safety in humans.