Do gun control laws reduce violence? To answer this question, a city-level cross-sectional analysis was performed on data pertaining to every U.S. city with a population of at least 25,000 in 1990 (n = 1,078), assessing the impact of 19 major types of gun control laws, and controlling for gun ownership levels and numerous other possible confounders. Models were estimated using instrumental variables (IVs) regression to address endogeneity of gun levels due to reverse causality. Results indicate that gun control laws generally show no evidence of effects on crime rates, possibly because gun levels do not have a net positive effect on violence rates. Although a minority of laws seem to show effects, they are as likely to imply violence-increasing effects as violence-decreasing effects. There were, however, a few noteworthy exceptions: requiring a license to possess a gun and bans on purchases of guns by alcoholics appear to reduce rates of both homicide and robbery. Weaker evidence suggests that bans on gun purchases by criminals and on possession by mentally ill persons may reduce assault rates, and that bans on gun purchase by criminals may also reduce robbery rates.