Social health-our ability to access and maintain meaningful human relationships-is recognized as a critical determinant of population health and climate change resilience, yet it is poorly integrated into climate change policy and research. This narrative Review synthesizes interdisciplinary evidence of the bidirectional and nuanced relationship between climate change and social health: climate change disrupts key social conditions (including housing stability and community cohesion), while widespread social disconnection limits our collective capacity to address the climate crisis. We unpack how social health can function as both a climate vulnerability and a lever for climate action. We present a new conceptual framework, describing the pathways through which social health and climate outcomes interact. Finally, we highlight existing evidence gaps and opportunities for public policy development and call for climate and health governance to centre social health as a key pillar of resilience in a changing world.