The COM-B model of behavior change proposes that to engage in a behaviour (B) at any given moment, a person must be physically and psychologically able (C) and have the opportunity (O) to exhibit the behavior, as well as the want or need to demonstrate the behaviour at that moment (M).

The COM-B behaviour change model is now used extensively in behaviour change interventions in the scientific literature. COM-B (‘capability’, ‘opportunity’, ‘motivation’ and ‘behaviour’) model. This model recognises that behaviour is part of an interacting system involving all these components.