<p>The association between anxiety and social avoidance among college students is receiving growing attention, however, the mediating and moderating mechanisms underlying the association remain largely unknown. This study explores the link between anxiety and social avoidance, examining whether depression and interpersonal trust mediates this association and the potential moderating effect of happiness.&#xa0;Convenient sampling method was adopted, 1023 college students aged 18 to 24 years old (640 males and 403 females) participated in this research. Adolescents were recruited to complete scales measuring self-rating anxiety, self-rating depression, social avoidance and distress, interpersonal trust and overall happiness.&#xa0;We found that anxiety was positively correlated with college students’ social avoidance as well as depression, and was negatively correlated with interpersonal trust. Depression was also positively correlated with social avoidance while interpersonal trust negatively correlated with social avoidance. Depression and interpersonal trust mediated the effect of anxiety on social avoidance, the relationship between depression and social avoidance was moderated by happiness, with a large moderating effect for higher happiness than lower ones.&#xa0;The findings from this study’s moderated mediation model suggest that educators should pay more attention to anxiety of college students with high depression and low interpersonal trust, especially give more support of happiness, so that they can provide more appropriate interventions.</p>