Bacteriocins are usually viewed as the effective weapons of bacterial killers. However, killing competitors with bacteriocins may be not only a means of eliminating other strains, but also a crucial unappreciated mechanism promoting bacterial diversity. In the present short review, we summarize recent empirical and theoretical studies examining the role bacteriocins that may play in driving and maintaining diversity among microbes. We conclude by highlighting limitations of current models and suggest directions for future studies.