This study assessed links between free-time activities in middle childhood (hobbies, sports, toys and games, outdoor play, reading, television viewing, and hanging out) and school grades, conduct, and depression symptoms both concurrently and 2 years later, in early adolescence. It also explored two mechanisms that might underlie activity-adjustment links: whether the social contexts of children's activities mediate these links, child effects explain these connections, or both. Participants were 198 children (M = 10.9 years, SD = .54 years) in Year 1, and their parents. In home interviews in Years 1 and 3 of the study, mothers rated children's conduct problems, children reported on their depression symptoms, and information was collected on school grades from report cards. In seven evening phone interviews, children reported on the time they spent in free-time activities during the day of the call and their companions in each activity. Links were found between the nature of children's free-time activities and their adjustment. The social contexts of free-time activities explained activity-adjustment links to a limited degree; with respect to child effects, evidence also suggested that better adjusted children became more involved in adaptive activities over time.