UNLABELLED: Previous research has identified the contemporaneous association between experiential avoidance, depression, and Internet addiction. However, the mechanisms underlying this association are not well acknowledged. The present study aimed to use cross-lagged panel modeling to examine whether depression mediates the relation between experiential avoidance and Internet addiction and whether gender plays a role in the relation. A total of 2731 participants (934 male, Mean=18.03) were recruited from a university at the baseline study (December 2019). Data was collected at all 3 time points across one year (2019?2020), using 6-month intervals. Experiential avoidance, depression and Internet addiction were assessed using the Acceptance and Action Questionnaire-II (AAQ-II), the Beck Depression Inventory-II (BDI-II) questionnaire, and Young?s Internet Addiction Test (IAT), respectively. Cross-lagged panel models were used to evaluate the longitudinal association and the mediating effect. Multigroup analyses were conducted to examine gender differences in the models.Cross-lagged models indicated that experiential avoidance significantly predicted subsequent depression, and depression significantly predicted subsequent Internet addiction. Furthermore, mediation analyses showed that depression has a mediating effect in the relation between experiential avoidance and Internet addiction ( = 0.010, 95%CI[0.003, 0.018], >0.001). Multigroup analyses demonstrated that the pattern of structural relations stayed consistent across gender. The findings indicated that experiential avoidance is indirectly related to Internet addiction through depression, suggesting that treatments targeted at reducing experiential avoidance could help relieve depression and thus decrease the risk of Internet addiction. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12144-023-04511-6.