In the past decade, policy-making around the world has increased its attention to behavioural insights (BI). The European Commission (EC) identified this trend early on and has incorporated BI to its policy-making over several years.

However, this experience has not been formally documented, or systematically analysed, from a policy studies perspective, leaving a large amount of experience-based knowledge on behavioural governance untapped.

Our contribution aims at closing this gap, clarifying the practices by which BI are gaining epistemic authority and contributing to the European Union's (EU) policy instruments. This paper presents the evolution of BI thinking inside the EC, illustrates how BI are introduced in the policy cycle, and explores future challenges to and opportunities for mainstreaming BI at every level and stage of policy-making in the EU.