Despite the potential benefits of social media use in late adulthood, adoption rates remain low among older adults. Research highlights the importance of age-specific factors, such as self-perceptions of aging (SPA), in technology adoption. However, the direction of the relationship between SPA and social media use remains unclear, with studies reporting mixed results. This study addresses this gap by examining (1) the reciprocal associations between SPA and social media use and (2) whether these relationships differ by gender and age. Using data from the 2014 and 2018 waves of the Health and Retirement Study, we analyzed 4,101 older Americans (age ≥65) with normal baseline cognition. Autoregressive cross-lagged analyses were conducted to assess reciprocal associations between SPA and social media use in the total sample and by subgroups. Results showed that more frequent social media use marginally predicted higher positive SPA, while higher negative SPA marginally predicted less frequent social media use. Gender-stratified analyses revealed that the positive effect of social media use on positive SPA was significant only among older men (B = 0.04, p < .05), whereas the negative effect of SPA on social media use was significant only among older women (B = −0.13, p < .01). Age-stratified analyses did not reveal any significant cross-lagged effects. These findings demonstrate that the reciprocal associations between SPA and social media use vary by the valence of SPA (positive/negative) and gender. Future interventions aimed at promoting positive SPA and digital technology use among older adults should adopt gender-tailored approaches.