Tobacco-policy interventions are designed to change the environment with the ultimate goal of preventing young people from beginning to smoke or reducing the likelihood that they will accelerate and solidify their smoking patterns. Several studies show that smoking bans in the home, at school, at work, and in the community are associated with less progression to smoking, less consolidation of experimental into regular smoking, and more quitting among adolescents and young adults. Randomized community trials and cohort studies support an association between enforcement of youth access laws against businesses and lower adolescent smoking rates. Several decades of studies provide evidence that increasing cigarette price through excise taxes reduces smoking among adolescents and young adults, who are particularly price-sensitive. Ongoing surveillance of tobacco-use behaviors in adolescents and young adults is essential for monitoring smoking patterns and evaluating tobacco policies.