Behavior change interventions have made an indelible mark on addressing problems that require behavioral solutions; however, such interventions also come at a financial cost. Identifying whether the benefits of behavioral changes are greater than the cost of the intervention itself, and the relative return on those costs compared to alternative opportunities, is critical to ensuring that behavior change interventions are truly beneficial and maximize the return on scarce resources. Cost-effectiveness analysis (CEA), as a form of economic evaluation that has been widely used, can provide evidence to inform decisions on whether funding bodies should fund these interventions or otherwise. The aim of this chapter is to outline the methods and approaches to CEA of behavior change interventions and discuss the role of economic evaluation in this setting. The chapter starts by presenting a framework for conducting economic evaluations of behavior change interventions. The framework sets out how to identify participants, interventions, comparators, and outcomes for economic evaluation studies. The chapter then outlines the appraisal of CEA by applying the consolidated health economic evaluation reporting standards checklist. Finally, the chapter discusses the implications and recommendations for CEA, including discussion of the appropriate measurement of benefits, feasible model approaches, and issues underlying political considerations when funding behavior change interventions.