<p>Psychological distress is a risk factor for internet addiction, yet mechanisms linking distress to the addiction, particularly through self-esteem, remain underexplored. Integrating Problematic Internet Use (PIU) theory and Scar theory, this two-wave study examined how depression and anxiety were differentially associated with internet addiction, with self-esteem as a mediator in 218 Vietnamese adolescents (<i>M</i>_age 13.3, <i>SD</i> = 0.82; 49.5% girls). Two single mediation models (using PROCESS Model 4) and one multiple mediation model (using structure equation modeling) were tested, controlling for age, gender, and the alternate distress variable (anxiety for depression model, depression for anxiety model). Results revealed that depressive symptoms measured at Time 1 were indirectly associated with internet addiction at Time 2 via self-esteem, while anxiety showed no indirect effects. Neither depression nor anxiety was directly associated with internet addiction. School-based interventions, including cognitive-behavioral therapy (CBT) and non-cognitive skill trainings, complemented with emotion regulation and social support strategies, may reduce internet addiction risk in adolescents with depressive symptoms. Limitations include the two-wave design, concurrent self-esteem and internet addiction measurement at the same time point, self-report biases, a broad conceptualization of self-esteem, omitted mediators (e.g., impulsivity, emotion regulation), and unaddressed confounders (e.g., socioeconomic status (SES), peer dynamics). Future research should employ multi-wave designs, diverse samples, and additional measures to enhance causal insights.</p>