OBJECTIVE: Extend findings with young children by examining the strength of association of activity level, parent mental distress, and parental involvement and monitoring with fifth graders' unintentional injuries. METHODS: Ordinal logistic regression models were used to predict unintentional injury frequency among 4745 fifth-graders. Examined predictors included demographics, parent reports of mental distress, temperamental activity level (tendency to be fidgety, restless, and constantly in motion), and parental involvement and monitoring in adolescents' lives. RESULTS: Higher levels of both activity level and parent mental distress predicted more frequent injuries. CONCLUSIONS: As has been found with younger children, unintentional injuries in fifth graders are associated with both parent and child characteristics. The result is discussed in the context of adolescent development. Implications include those for injury prevention (multi-dimensional prevention strategies that incorporate environmental modifications as well as training of youth and parents) and future research (study of potential mechanisms behind injury risk behavior via longitudinal and experimental research; study of injury risk during this phase of child development).