Loneliness is a major public health concern due to its serious health and well-being consequences. A range of interventions have been developed to combat loneliness, with group-based approaches showing the most promise. This finding accords with decades of research pointing to the importance of group belonging for health and well-being in general. Nevertheless, loneliness interventions are seldom guided by theory targeting these group processes. As a result, it is unclear how social group processes can be harnessed to address and prevent loneliness more effectively. We begin this chapter by outlining the burden of loneliness and reviewing the efficacy of group-based approaches developed to offset this burden. We then introduce a social identity analysis, which suggests that unlocking the largely untapped potential of social group processes is key to enhancing loneliness interventions. Our arguments focus on how this might be achieved in collective and whole- of-community approaches to loneliness. In doing so, our hope is that the unique contribution of group belonging will be leveraged and prioritised in the process of developing more effective and impactful solutions to managing and preventing loneliness.