We know very little about the development of rumination, the tendency to passively brood about negative feelings. Because rumination is a risk factor for many forms of psychopathology, especially depression, such knowledge could prove important for preventing negative mental health outcomes in youth. This study examined developmental origins of rumination in a longitudinal sample (N=337; 51% girls) studied in preschool (ages 3½ and 4½ years) and early adolescence (ages 13 and 15 years). Results indicated that family context and child temperament, assessed during the preschool period, were risk factors for a ruminative style in adolescence. Specifically, early family contexts characterised by over-controlling parenting and a family style of negative-submissive expressivity predicted higher levels of later rumination. These associations were moderated by children's temperamental characteristics of negative affect and effortful control. Further, the interaction of these temperament factors exerted an additional influence on later rumination. Implications for prevention and intervention efforts are discussed.