Legislation to ban smoking indoors in public places is now commonplace, driven mainly by the need to protect non-smokers from exposure to secondhand smoke. A new domain for tobacco control policy is outdoor settings, where secondhand smoke is usually less of a problem. However, the ethical justification for outdoor smoking bans is compelling and is supported by international law. The central argument is that outdoor bans will reduce smoking being modelled to children as normal behaviour and thus cut the uptake of smoking. Outdoor smoke-free policies may in some circumstances (such as crowded locations like sports stadiums) reduce the health effects of secondhand smoke1; will reduce fires and litter2; and are likely to help smokers’ attempts at quitting.