<p><b>BACKGROUND: </b>This study examined whether social factors, including social support, social networks, and familism, modify the longitudinal association between ACEs and epigenetic age acceleration (EAA).</p><p><b>METHODS: </b>We analyzed DNA methylation (DNAm) profile data from two visits (approximately six years apart) among 960 Hispanic/Latino adults in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). GrimAge epigenetic age and DunedinPACE pace of aging were used. Linear mixed models examined effect modification of social support, social networks (network diversity and the number of embedded networks), and familism (family obligation, support, and as referents) on the association between high vs. low-to-moderate ACEs (i.e., ≥ 4 vs. < 4 ACEs) and repeatedly measured EAA. Models adjusted for age, sex, parental education, childhood economic hardship, nativity, and cell-type proportions. We also dichotomized the levels of social support and both subscales of social networks to low (≤ 75th percentile) and high (> 75th percentile), and assessed joint effect modification by social support and networks.</p><p><b>RESULTS: </b>The mean difference in GrimAge acceleration (AgeAccelGrim) between high and low-to-moderate ACEs was statistically significantly attenuated when social support levels were higher (β for interaction = -0.73 years; 95 % CI: -1.23, -0.24; p = 0.003). No evidence of effect modification was found for social networks or familism. Having only high social support (β for interaction = -1.40 years; 95 % CI: -2.79, -0.01; p = 0.049) or both high social support and network diversity (β for interaction = -1.57 years; 95 % CI: -2.72, -0.42; p = 0.008) significantly decreased the mean difference in AgeAccelGrim between high and low-to-moderate ACEs.</p><p><b>CONCLUSION: </b>Social support may independently buffer the adverse impact of ACEs on biological age acceleration among Hispanic/Latino adults, and the buffering effect may be stronger when accompanied by diverse social networks.</p>