There is little doubt that nicotine addiction sustains tobacco use in most people and that individual variation in response to tobacco has a strong biological basis. However, the great diversity in tobacco use behaviors observed between countries and within countries over time suggests that biology alone cannot fully explain these variations. This review examines the role of the social environment in understanding tobacco use behaviors and efforts to curb tobacco use at the population level. We conclude that the social environment plays a critical role in determining how innate biological factors involved in nicotine dependency actually get expressed at the population level. Tobacco use as reflected in population trends is seen as the product of the interaction of agent, host, and environmental factors. Government policies are seen as an important modifiable environmental influence that can alter how tobacco products are designed and marketed (agent factors) and how consumers perceive the risks and benefits of smoking (host factors). Evidence suggests that synergy is gained when tobacco control interventions directed at agent, host, and environmental factors are implemented together.