We analyze the timing and pattern of adoption of “shall issue” concealed-carry handgun laws. “Shall issue” laws require the authorities to issue permits to qualified applicants; “may issue” laws give the authorities more latitude to reject applications. We find three factors influence the shift from “may issue” to “shall issue.” First, more urban states are less likely to shift to “shall issue,” although the size of this effect is quantitatively small. Second, the switch is influenced by the decisions taken by neighboring states. Third, we find evidence that increases in the crime rate accelerated the switch to “shall issue.