Less than 20% of adult cancer survivors participate in physical activity and, as a result of such inactivity, cancer survivors are at increased risk for developing chronic diseases. Studies have linked social support as a predictor of physical activity participation in healthy adults. The primary goal of this systematic review is to examine the relationship between social support and physical activity engagement in adult cancer survivors and determine whether additional research is needed in this area. Several databases were searched and articles were systematically extracted according to the inclusion and exclusion criteria. That search yielded 69 articles, 22 of which were identified and included in this review. Fifty percent of the studies showed a significant relationship between social support and physical activity engagement; however, 59% of the participants were breast cancer survivors. The findings suggest that additional research is needed to develop social support strategies that will increase physical activity engagement in adult survivors of cancers other than breast cancer.