This chapter provides an overview of the use of affect-based interventions to change behavior. Affect is defined in terms of affect proper and affect processing; both of these terms are used regularly in research on affect interventions. The evidence of direct modification of these affect constructs is then reviewed. Based on this evidence, step-by-step guides to techniques focusing on changing two key aspects of affective processing are provided: changing affective attitudes and anticipated affect. The guides to these techniques include typical means of delivery, target audience, behaviors, enabling or inhibiting factors, training and skills required, intensiveness, typical materials needed, and typical examples of implementation. In addition, application of implementation intentions, fear appeals, evaluative conditioning, and exercise games as other ways to change affect as a means to changing behavior are reviewed. Finally, two additional intervention pathways that could have impact on behavior change are reviewed: direct modification of other sources of behavioral influence (e.g., traditional social cognitive factors) in order to overcompensate for the impact of affect and self-regulation of the intensity of the affect experience as a means of inhibiting its impact.