Recent comparative studies have suggested that RLPs are forming new networks and links with social movements (SMs). This chapter maps the linkage attempts of the RLPs studied in this Handbook. It identifies four distinct ‘theses’ regarding the development of the links between RLPs and SMs. Those include the position that the two actors operate in ‘separate spheres’, an interpenetration scenario, a co-variation thesis according to which the two actors are in the process of mutual detachment and finally a co-evolution thesis, that focuses on the changing nature of those linkages. Current empirical research predominantly vindicates the co-evolutionary thesis. The chapter develops expectations about the key factors that shape these linkages. By mapping the nature and scope of RLPs’ societal linkage during the Great Recession, it shows that there is a considerable degree of variation in the links that RLPs have developed with SMs. These differences can be explained by several factors, but the most significant is the ideological and organisational heterogeneity within the radical left party family.