This paper considers the association between social support, conceived and assessed from a social-psychological perspective, and psychological well-being. The magnitude and consistency of the relationship are evaluated across four studies involving very diverse populations. Evidence is also presented on causal ordering and the distinctiveness of the social support and psychological well-being dimensions, and on the question of whether social support has pervasive effects or functions only, or primarily, as a buffer in the face of unusual difficulty. Findings across the four studies suggest a modest, but reliable, association between the experience of social support and psychological well-being. Evidence is also presented consistent with the view that some part of the causation involved goes from social support to psychological well-being and vice versa, and indicating that the two variables have different major determinants. Evaluation of the effects of level of stress upon the support/well-being relationship suggests that social support has significant main effects, that it is most important in stressful circumstances, and that these relationships vary across social class groupings.