Breast cancer remains one of the most prevalent and lethal malignancies worldwide, with therapeutic resistance and tumour recurrence posing significant clinical challenges. Restoration of the tumour suppressor genes, frequently mutated or inactivated in breast cancers, represents a promising therapeutic strategy. In this study, we explore the use of extracellular vesicles (EVs) as a novel, biocompatible delivery system for the functional reintroduction of functional tumour suppressor proteins into breast cancer cells. Characterization confirmed successful loading and preservation of EV integrity and cargo stability. In vitro experiments demonstrated efficient uptake of loaded EVs by breast cancer cell lines, resulting in reactivation of downstream apoptotic pathways, cell cycle arrest, and significant inhibition of cell proliferation. In vivo, systemic administration of tumour-suppressor loaded EVs in murine models led to suppressed tumour growth and enhanced survival without observable off-target toxicity. These findings highlight the therapeutic potential of EV-mediated gene delivery and support further development of this platform as a targeted, non-viral approach for breast cancer therapy.