Objective: Social support and social integration have been linked to lower rates of morbidity and mortality. However, the biological mechanisms responsible for such links need greater attention to advance theory and unique intervention opportunities. The main aim of this article was to conduct a meta-analytic review of the association between social support–social integration and inflammatory cytokines (e.g., interleukin-6, C-reactive protein) and test several proposed moderators from prior qualitative reviews. Method: A literature search was conducted using the ancestry approach and with databases PsycInfo, Medline, and EMBASE by crossing the exact keywords social support or social integration with inflammation. The review identified 41 studies with a total of 73,037 participants. Results: The omnibus meta-analysis showed that social support–social integration were significantly related to lower levels of inflammation (Zr = −.073). These results were not moderated by the operationalization of social relationships or the type of population, cytokine, and design. Conclusions: These data suggest that inflammation is at least one important biological mechanism linking social support and social integration to the development and course of disease. Future work should continue to build on this review and address next-generation questions regarding antecedent processes, mechanisms, and other potential moderators.