Background: Breast cancer remains the second most common malignancy worldwide, with approximately 2.3 million new cases diagnosed in 2022, underscoring the urgent need for effective, low-toxicity adjunct therapies. Conventional treatments such as chemotherapy often induce severe myelotoxicity and resistance, prompting exploration of natural agents like wheatgrass (Triticum aestivum), a nutrient-dense young grass rich in chlorophyll, flavonoids, and antioxidants. Objectives: This review synthesises evidence on the anticancer potential of wheatgrass against breast cancer, focusing on molecular pathways (e.g., apoptosis induction, cell cycle arrest) and translational insights from preclinical to clinical studies. Key Findings: In vitro studies demonstrate wheatgrass extracts' cytotoxicity against breast cancer cell lines (MCF-7, MDA-MB-231), enhancing under simulated microgravity via unique bioactives like apigenin and tocopherol, which downregulate PI3K/AKT, NF-κB, and DNA repair genes while upregulating pro-apoptotic factors. Phytochemicals such as flavonoids inhibit proliferation, angiogenesis (VEGF suppression), and metastasis. In vivo models show tumour reduction and immune modulation (e.g., TH1 cytokine upregulation). Clinically, pilot trials indicate wheatgrass juice reduces chemotherapy-induced neutropenia and anaemia in breast cancer patients, with no reported adverse events, though large-scale RCTs are lacking. Implications: Wheatgrass holds promise as a safe adjunct to mitigate treatment toxicities and enhance efficacy through targeted pathways, warranting further pharmacokinetic optimization and phase II trials for personalised integration in breast oncology.