Outer-membrane vesicles (OMVs) are spherical buds of the outer membrane of Gram-negative bacteria, containing outer-membrane lipids and proteins, and soluble periplasmic content. They are not the products of cell lysis but are produced through a process involving the dissociation of the outer membrane from the underlying peptidoglycan (PG) layer. OMVs have diverse functions, including promoting pathogenesis, enabling bacterial survival during stress conditions, and regulating microbial interactions within bacterial communities. Recent studies have revealed that OMVs are produced through various mechanisms and that their biogenesis is influenced by factors such as temperature, nutrient availability, and envelope-targeting antibiotics. OMVs can carry a variety of molecules, including virulence factors, and are involved in bacterial pathogenesis, nutrient acquisition, and interbacterial communication. OMVs also play a role in stress responses, such as oxidative stress, and in the dissemination of genetic material. Additionally, OMVs can act as 'public goods' by benefiting both the producing bacteria and other bacteria. OMVs have been shown to mediate antibiotic resistance and contribute to bacterial survival in various environments. The study of OMVs has expanded to include their potential applications in bioengineering and their role in bacterial communities.Outer-membrane vesicles (OMVs) are spherical buds of the outer membrane of Gram-negative bacteria, containing outer-membrane lipids and proteins, and soluble periplasmic content. They are not the products of cell lysis but are produced through a process involving the dissociation of the outer membrane from the underlying peptidoglycan (PG) layer. OMVs have diverse functions, including promoting pathogenesis, enabling bacterial survival during stress conditions, and regulating microbial interactions within bacterial communities. Recent studies have revealed that OMVs are produced through various mechanisms and that their biogenesis is influenced by factors such as temperature, nutrient availability, and envelope-targeting antibiotics. OMVs can carry a variety of molecules, including virulence factors, and are involved in bacterial pathogenesis, nutrient acquisition, and interbacterial communication. OMVs also play a role in stress responses, such as oxidative stress, and in the dissemination of genetic material. Additionally, OMVs can act as 'public goods' by benefiting both the producing bacteria and other bacteria. OMVs have been shown to mediate antibiotic resistance and contribute to bacterial survival in various environments. The study of OMVs has expanded to include their potential applications in bioengineering and their role in bacterial communities.