First paragraph: There is now widespread acceptance that behaviour plays a key role in the development of many long-term conditions and that behaviour change is essential for both prevention and treatment (Khaw et al., 2008; Mokdad, Marks, Stroup, & Gerberding, 2004). Our discipline has taken important strides forward in theory development and in extending our understanding of the factors that guide intention formation and behavioural enaction. Significant advances are also being made in developing a reliable taxonomy of behaviour and behaviour change techniques (Michie et al., 2013). However, Health Psychology now needs to start to deliver robust evidence that our interventions can lead to lasting changes in behaviour, which in turn, lead to significant health benefits. ; Output Type: Editorial