Around 19% of US adults smoke cigarettes, and smoking remains the leading avoidable cause of death in this country. Without treatment only ~5% of smokers who try to quit achieve long-term abstinence, but evidence-based cessation treatment increases this figure to 10% to 30%. The process of smoking cessation comprises different pragmatically defined phases, and these can help guide smoking treatment development and evaluation. This review evaluates the effectiveness of smoking interventions for smokers who are unwilling to make a quit attempt (motivation phase), who are willing to make a quit attempt (cessation phase), who have recently quit (maintenance phase), and who have recently relapsed (relapse recovery phase). Multiple effective treatments exist for some phases (cessation), but not others (relapse recovery). A chronic care approach to treating smoking requires effective interventions for every phase, especially interventions that exert complementary effects both within and across phases and that can be disseminated broadly and cost-effectively.