This chapter examines the outcome expectancy construct as it relates to physical activity (PA) behavior. It discusses cross-cutting conceptual issues that are particularly important for the relationship between outcome expectancy and PA behavior, including the importance of outcome value, distinctions between instrumental versus affective outcome expectancies, perceived outcome proximity, and conceptual similarities between assessments of outcome expectancy and self-efficacy. The chapter discusses how outcome expectancy is incorporated into each of these commonly used health behavior theories. It presents associated future research considerations as well as highlights the practical implications of these issues for PA-promoting message design. The chapter highlights several approaches to conceptualizing outcome expectancies in prominent theories of health behavior. It reviews issues regarding the incorporation of outcome expectancies in the operationalization of self-efficacy, and encourage investigators to devote effort toward the sensitivity and specificity of measurement options in this area.