A theory of human change describes not only what changes but also how and why a change occurs within a specific context. This chapter provides an overview of several of the theories of behavior change that are most pertinent to the mind-body wellness space. The health belief model (HBM) is a framework that helps us to understand how and why people change their wellness behaviors by assessing six aspects of the person’s beliefs about health and wellness: perceived susceptibility to the problem, perceived severity of the problem, perceived benefits to treatment, perceived barriers to treatment, cues to action, and self-efficacy. The theory of planned behavior (TPB) evaluates our intention to enact a wellness behavior, our evaluation of subjective norms surrounding the behavior, and our ability to control/influence this behavior. The Stages of Change or Transtheoretical model identifies the six stages of change for health-related behaviors (precontemplation, contemplation, preparation, action, maintenance, and termination) and proposes the process by which people move through these stages. Finally, social cognitive theory (SCT) is a theory about how we learn and proposes that we are not passive recipients of wellness promotion; we are embedded in a dynamic network of person, environment, and behavior, in which we are actors, recipients, and inventors of our outcomes.