The authors review studies on time use of children and adolescents around the world and discuss developmental implications of population differences. Industrialization and schooling are linked to dramatic declines in time spent on household and wage labor. This labor is often unchallenging, sometimes hazardous; developmental benefits often do not increase above a limited number of hours; hence, reduction in these activities opens time for activities that may be more developmentally beneficial. Adolescents in East Asian postindustrial societies spend this freed-up time in schoolwork, a use associated with lower intrinsic motivation but high achievement and economic productivity. Adolescents in North America spend more time in leisure, associated with greater self-direction but of an uncertain relation to development. Age, gender, and socioeconomic differences in activities and with whom time is spent are also considered.