The death of a parent or sibling (family bereavement) is associated with mental health problems in approximately, 25 % of the affected children. However, it is still unknown whether mental health problems of family-bereaved adolescents are predicted by pre-existing mental health problems, pre-loss family functioning, or multiple bereavements. In this study, a prospective longitudinal assessment of change in mental health following bereavement was done in a large representative sample from the 'Tracking Adolescents Individual Lives Survey' (TRAILS). This is a four-wave prospective cohort study of Dutch adolescents (n = 2230) of whom 131 (5.9 %) had experienced family bereavement at the last wave (T4). Family-bereaved adolescents reported more internalizing problems, within 2 years after family bereavement, compared to the non-bereaved peers, while taking into account the level of internalizing problems before the bereavement. A clinically relevant finding was that 22 % new cases were found in family-bereaved, in comparison to 5.5 % new cases in non-bereaved. Low SES predicted more internalizing problems in family-bereaved but not in non-bereaved adolescents. Family functioning, reported by the adolescent, did not predict mental health problems within 2 years. Multiple family bereavements predicted fewer externalizing problems. In conclusion, internalizing problems increase in adolescents after family bereavement in comparison to non-bereaved and these can be predicted by pre-loss factors. Awareness among professionals regarding the risks for aggravation of mental health problems after family loss is needed.