Behaviour change is essential to improve population health, the self-management of illness, chronic conditions and health professional practice. Evidence about behaviour change interventions is currently being produced at such a rate that manual systems for evidence review and synthesis cannot keep up. Neither can they account for all the relevant features of interventions. The Human Behaviour-Change Project (HBCP) aims to bring together behavioural scientists, computer scientists and system architects to advance progress in behaviour change. It aims to answer variants of the ‘big question’ of behaviour change: ‘What works, compared with what, how well, with what exposure, with what behaviours (for how long), for whom, in what settings, and why?’ The main outputs will be: 1) an ontology of behaviour change interventions; 2) an AI system capable of extracting and interpreting evidence from published literature and making predictions; 3) an interface allowing users (researchers, policy-makers, practitioners) to access the knowledge base and answer specific questions about behaviour change.