In 2022, the US Supreme Court affirmed the constitutional right of most civilians to carry concealed firearms in public for self-defense, overturning restrictive concealed carry laws in several states. Concealed carry regulations have evolved substantially through four waves of reforms, beginning with prohibitions of the practice in the nineteenth and early twentieth centuries to today‘s permitless-carry regimes in more than half of US states. In recent decades, competing claims about whether permissive concealed carry regulations deter or exacerbate criminal violence have been studied with increasing rigor, with the weight of evidence now showing that such laws cause increases in homicide and violent crime rates. We review the limited available research examining the mechanisms by which permissive concealed carry laws increase violence and the evidence that specific law provisions may contribute to those effects. This review is intended to inform ongoing decisions and debates about concealed carry regulations and their impact on violence in America.