Purpose <p>This study synthesized existing research to assess the linkage between social support mechanisms and perceptions of hopelessness in cancer patients, while exploring factors that may modulate this relationship.</p> Methods <p>Relevant literatures were identified through four databases. After quantifying the overall effects, the results from meta-regression and subgroup analyses were comprehensively compared to thoroughly investigate the potential moderating effects.</p> Results <p>This study identified 22 studies. The results of this research displayed a moderate negative correlation was found between social support and hopelessness. Moderator analyses revealed that the choice of hopelessness measure significantly influenced effect sizes. Compared with the Beck Hopelessness Scale, the correlation between social support and hopelessness applying the Mental Adjustment to Cancer Scale was lower. In developing countries, social support had a stronger protective effect compared to developed countries. Publication year and cancer type did not significantly moderate the relationship.</p> Conclusion <p>This study revealed that social support was one of the important protective factors influencing the sense of hopelessness among cancer patients. These findings emphasized the significance of incorporating social support strategies into cancer care programs, particularly in developing countries, providing a theoretical basis for tumor care.</p>