Objective <p>The aim of this study was to investigate the association between social media addiction and depression among university students of different genders in Wuhan, China, and also to explore the effect of social support on depression in the context of social media addiction.</p> Methods <p>Three waves (2020–2023) of psychological optimism and health data were analyzed. In all waves, 1,215 university students aged 16 to 22 years provided the data. Statistical analyses included constructing single- and multi-group latent growth curve models.</p> Results <p>Of the 1215 participants, 748 (61.6%) were girls. Throughout the single-group latent growth curve model, girls had lower depression scores at baseline (i=-0.099, Z = -2.842) and increased linearly over time (s=-0.121, Z = -2.377). Throughout the single-group latent growth curve model, boys had higher depression scores at baseline (i = 3.506, Z = -2.612), and increased linearly over time (s=-1.229, Z = 0.210),while girls had lower depression scores at baseline (i = 0.345, Z = 0.289), and increased linearly over time (s = 0.336, Z = 0.414). Social media addiction was associated with depression scores for both genders across all time periods. The coefficients for boys on social media at each of the three points in time were 3.272; 4.904; 9.522. The coefficients for girls on social media at each of the three points in time were 5.521; 4.406; 6.001. Social support and depression were related for girls with coefficients at the first time point of -0.208 and coefficients at the third time point of-0.258.</p> Conclusion <p>The findings suggest that social media addiction is associated with higher depression scores among university students. Male students’ social support was not associated with depression. In contrast, social support for female students was associated with lower depression scores in the first and third years of university.</p>