Donors, governments and anti-corruption practitioners seeking alternative tools to address systemic corruption are increasingly turning to behavioural science. Behavioural anti-corruption approaches appear promising because they respond to a growing body of descriptive evidence on how certain social norms and mental models drive corruption, particularly in fragile contexts. Interventions that target social norms and seek to shift people’s behaviours away from corrupt practices could be more effective and long-lasting than ones that, for example, simply add more regulations and controls.