ABSTRACT Previous studies have shown that bullying victimisation is a significant risk factor for problematic media use. However, little is known about the underlying mechanisms involved in this link. This study aimed to examine the association between bullying victimisation and problematic media use among primary school students, as well as the mediating effect of depression and the moderating effect of teacher–student relationships on this association. A total of 341 participants (10.73 ± 0.68 years) from a Chinese primary school completed the structured questionnaire with respect to the study variables. The results showed that depression mediated the association between bullying victimisation and problematic media use and that teacher–student relationships moderated the second stage (depression to problematic media use) of the mediation model. The simple slope analysis indicated that the association between depression and problematic media use was not significant when the relationship between teachers and students was high (bsimple = 0.03, t = 0.30, p > 0.05). As students perceived low levels of relationships with teachers, depression had a significant effect on problematic media use (bsimple = 0.32, t = 3.34, p < 0.01). These findings can provide empirical support for formulating problematic media use intervention measures based on the bullying victimisation experience as well as the important role of depression and teacher–child relationships.