Around one-third of the European Union’s budget is dedicated to cohesion policy, which promotes and supports the overall harmonious development of its Member States and regions. The success of this investment relies on effective partnerships among governments, stakeholders, and citizens. Citizens have a key role to play in shaping decisions on public investment, as well as in making public authorities more transparent and accountable. From July 2020-December 2021, the European Commission and the OECD partnered to explore how five authorities across Europe could place citizens at the centre of their investment decisions. This report summarises lessons learned throughout this project and, particularly, the results of applying innovative citizen participation methods to cohesion policy more broadly.