Probiotics are widely recognized for their health benefits, particularly in disease prevention and treatment. Recent research suggests that their therapeutic effects may be linked to the bacterial membrane vesicles (bMVs) they release. These nanoscale vesicles, secreted during probiotic growth and metabolism, facilitate intercellular communication through efficient material transport and signaling. With their biocompatibility and targeting properties, probiotic bMVs hold promise for medical applications. This review examines their biogenesis, bioactive components, functions, and role in disease treatment, while also discussing future research directions to unlock their full therapeutic potential.