Social support is one of the factors that influence achievement motivation. Social support received can make individuals feel calm, cared for, self-confident, and competent. This study aims to determine the effect of social support on achievement motivation in athletic athletes. The type of research is ex post facto. The population is the athletics athletes of the Glagah Wangi Demak athletic club totaling 37 athletes with an age range of 14-19 years. The instrument in this research is a questionnaire. Data analysis using a simple regression test. The results showed that there was a significant effect of social support on the achievement motivation of athletic athletes. The contribution of social support to achievement motivation in athletic athletes is 27.90%. The better the athlete's social support, the higher the achievement motivation. It is hoped that people around athletes, such as parents, coaches, and friends, will provide the support that can help athletes so that they have a positive impact on their achievements. Athletes must maintain and develop enthusiasm while undergoing the best possible training program. Parents always encourage their children and provide good infrastructure to support children's achievements.