The Theory of Planned Behavior (TPB), developed by psychologist Icek Ajzen in 1985, is a psychological model that links an individual's beliefs to their behavior. It significantly improved upon the earlier Theory of Reasoned Action (TRA) by introducing the crucial component of "perceived behavioral control." TPB proposes that an individual's behavioral intention, which is the most direct predictor of their actions, is determined by three core factors: their personal attitude towards the behavior, the subjective norms (social pressures) influencing them, and their perceived ability to perform the behavior.

This added concept of perceived behavioral control, drawing from Bandura's self-efficacy theory, emphasizes that people are far more likely to intend and successfully execute behaviors they believe they are capable of performing. By incorporating this element, TPB offers a more robust framework for predicting actual behavior in situations where an individual's control might be incomplete. The theory has been widely applied across numerous domains, from healthcare and advertising to consumer finance and sustainability, demonstrating its broad utility.