Technical Abstract: Social Cognitive Theory (SCT) addresses both the psychosocial dynamics influencing health behavior and methods for promoting behavioral change. Within SCT, human behavior is explained in terms of a triadic, dynamic, and reciprocal model in which behavior, personal factors (including cognitions), and environmental influences all interact. Among the crucial personal factors are the individual's capabilities to symbolize behavior, to anticipate the outcomes of behavior, to learn by observing others, to have confidence in performing a behavior (including overcoming the problems in performing the behavior), to self-determine or self-regulate behavior, and to reflect on and analyze experience (Bandura, 1997). Health educators and behavioral scientists have creatively used SCT to develop interventions, procedures, or techniques that influence these underlying cognitive variables, thereby increasing the likelihood of behavioral change. This chapter provides a brief history of the development of Social Cognitive Theory, includes a description of key concepts, and analyzes two recent examples of how the theory was used to design health education programs.