Research and Technology Organisations (RTOs) have developed in many European countries at both national and regional levels to assist in the support of local industry, often around specific industrial technologies or sectors. RTOs have an important role to play in smart specialisation (S3) though and three specific roles have been identified here. First, many RTOs have a policy role and have capabilities to identify industry needs and technological opportunities as a key input into the entrepreneurial discovery process. Second, RTOs, as increasingly international organisations, can facilitate the access to global knowledge for regional firms through their networks and research collaborations. Third RTOs often have a central role in the development of particular cluster groupings through their specialisation around core technologies, and as such can be a central player in the development of such clusters. But all three of these roles involve potential challenges and difficulties as the interests of the RTOs do not necessarily align with the needs of the region. The case studies in this report on RTOs in Spain, Finland, Italy, and the UK illustrate the variety of RTOs and the complexities of their relationships with regional hosts, but also some of the initiatives that are developing to support smart specialisation.