Several research literatures are reviewed that address the associations of emotional, informational, and instrumental social support to psychological adjustment to cancer. Descriptive studies suggest that emotional support is most desired by patients, and correlational studies suggest that emotional support has the strongest associations with better adjustment. However, the evidence for the effectiveness of peer discussion groups aimed at providing emotional support is less than convincing. Moreover, educational groups aimed at providing informational support appear to be as effective as, if not more effective than, peer discussions. Reasons for inconsistencies between the correlational and intervention literatures are discussed, and future directions are outlined.