Policy makers have become increasingly interested in the concept of ‘behaviour change’. Over the past forty years, both psychologists and economists have produced new empirical evidence about how individuals behave when presented with certain decisions or situations. Many of these findings questioned existing models of behaviour. In recent years, these findings have become popular in the UK government from both political and technocratic perspectives, and therefore have increasingly been incorporated into policy analysis and design. One of the most prominent developments was the creation of a Behavioural Insights Team in the UK Cabinet Office, which has worked across a variety of policy areas. In contrast, social marketing has suffered a decline in popularity and funding since 2010, and we suggest several reasons why this has happened. Finally, we discuss several common criticisms of the application of behavioural sciences to policy, and distinguished between those originating from philosophical and technocratic standpoints.