Bacterial extracellular vesicles (BEVs) are emerging as promising therapeutic agents and drug delivery vehicles due to their unique properties. These nanoscale vesicles possess stable membrane structure and naturally encapsulate a variety of bioactive molecules, making them versatile tools in biomedical applications. However, clinical translation of BEVs faces challenges such as insufficient display of disease-specific antigens, excessive toxicity, and rapid clearance. Addressing these issues is crucial for the clinical translation of BEVs. In this review, we discuss recent advances in BEV engineering strategies aimed at addressing these limitations and expanding their therapeutic applications. We highlight approaches for loading exogenous cargo into BEVs, detoxification strategies, and the latest progress in the application of engineered BEVs for treating infectious diseases, cancer, and other disorders. Despite promising preclinical results, clinical translation is hindered by safety concerns, standardisation difficulties, and scalability issues. Future research should focus on optimising detoxification processes, establishing global standardisation, and improving production methods to facilitate successful clinical translation of engineered BEVs. This review provides insights into the current status and future perspectives of BEV engineering for therapeutic applications.