Different theoretical frameworks have been developed to account for the impact of social connectedness on individual outcomes such as vulnerability and subjective well-being, in particular approaches based on social identity theory, on social networks, and on social capital. We review research that describes how such social connectedness approaches rooted in psychological, social-psychological and sociological traditions demonstrate the link between social relations, vulnerability and well-being.We summarize and compare key arguments of these approaches in terms of their views on the processes relating the collective-relational to the individual-psychological. Indeed, social connectedness is generally associated with positive individual outcomes (such as prevention of physical and mental health issues and improved subjective well-being).Under some circumstances, however, these positive effects weaken or disappear. We therefore discuss boundary conditions of these processes, by looking at research explaining variation of the relation between connectedness and well-being as a function of social conditions (e.g., structural inequality, weak social relations, or negative social identities).Last, we discuss specificities and commonalities between approaches, for example regarding bridging and bonding social capital, or intergroup and intragroup relations. We highlight the tensions between approaches and offer some guidelines regarding their most promising use as a function of one’s research goals.