The purpose of this study was to examine prospectively the impact of family transition on deviant development in a sample of 427 French-Canadian boys participating in a longitudinal study from kindergarten onwards. During the course of the study some boys experienced family transition. We grouped the boys by developmental period and number of marital transitions they experienced: divorced between ages 6 and 11; divorced between ages 12 to 15; remarried between ages 6 and 11; and remarried between ages 12 and 15. From ages 11 to 15 we assessed boys' delinquency and their family processes (parental supervision, punishment, and communication) annually. The results suggest that boys who experienced remarriage between ages 12 and 15 are at greater risk for delinquency. In particular, they showed evidence of comparatively more theft and fighting at earlier ages than their peers from families that had remained intact. At similar points in development, they perceived less expressive parent–child relationships. Finally, these boys also perceived less monitoring by their parents, both overall and at different points in adolescence.