As behavioural sciences are unearthing the complex cognitive framework in which people make decisions, policymakers seem increasingly ready to design behaviourally-informed regulations to induce behaviour change in the interests of the individual and society. After discussing what behavioural sciences have to offer to administrative law, this paper explores the extent to which administrative law may accommodate their findings into the regulatory process. After presenting the main regulatory tools capable of operationalizing behavioural insights, it builds a case for integrating them into public policymaking. In particular, this paper examines the challenges and frictions of behavioural regulation with regard both to established features of administrative law, such as the principle of legality, impartiality and judicial oversight and more innovative control mechanisms such as the use of randomized control trials to test new public policies. This analysis suggests the need to develop a legal framework capable of ensuring that behavioural considerations may inform the regulatory process while at the same time guaranteeing citizens' constitutional rights and freedoms vis-à-vis the Regulatory State.