<p>This study examined the psychological mechanisms linking childhood interpersonal trauma to social anxiety among college students, focusing on the mediating role of experiential avoidance and the moderating role of mentalized affectivity. Participants (<i>N</i> = 397) were South Korean college students (<i>M</i> = 23.3 years, <i>SD</i> = 2.4), with 53.1% identifying as women. Results from structural equation modeling with bootstrapping revealed the following: First, childhood interpersonal trauma was positively associated with both experiential avoidance and social anxiety, whereas mentalized affectivity was negatively associated with all three variables. Second, experiential avoidance partially mediated the relationship between childhood trauma and social anxiety. Third, mentalized affectivity moderated both the direct path from trauma to social anxiety and the indirect path through experiential avoidance. Fourth, the overall moderated mediation model was found to be statistically significant. These findings suggest that childhood interpersonal trauma contributes to social anxiety through increased experiential avoidance and that higher levels of mentalized affectivity may buffer both direct and indirect effects. Theoretical and clinical implications are discussed.</p>