This paper first presents four different conceptualizations of social support: social integration, satisfying relationships, perceived helpfulness and enacted support. Then, classic and contemporary social comparison theory and social exchange theory are analysed as they are two theoretical perspectives that arc particularly useful in understanding social support. These perspectives are employed to explain three seemingly paradoxical phenomena in the domain of social support: (1) the fact that support sometimes has negative effects; (2) the fact that the occurrence of stress itself can sometimes decrease the availability of support resources; and (3) the phenomenon that people believe that they give more support than they receive, and that there is more support available for them than for others.