The paper reviews the diffusion research approach to the analysis of innovations and its impact on innovation studies. This social approach brought a new understanding of the innovation process by focusing on analysing the factors that influence the spread of innovations instead of focusing on its technical basis. We also review the different approaches to the study of the spread of policies – policy diffusion, policy transfer and policy mobility. We review the reception of diffusion research in innovation studies to recover some insights and to integrate them into current innovation policy debate. We use the innovation policy of Smart Specialisation Strategies (S3) as an example of how this integration could be done. After reviewing the main challenges of S3, we show the importance of improving the implementation phase of innovation policies through different mechanisms. For example, we indicate the need of paying more attention to mechanisms of policy diffusion, such as learning and, specially, socialisation as these could lead to more stable and long-term policy changes.