We investigate how household disadvantage affects the time use of 15-18 year-olds using 2003-2006 data from the American Time Use Survey. Applying competing-risk hazard models, we distinguish between the incidence and duration of activities and incorporate the daily time constraint. We find that teens living in disadvantaged households spend less time in non-classroom schooling activities than other teens. Girls spend some of this time in work activities, suggesting they are taking on adult roles. However we find more evidence of substitution into unsupervised activities, suggesting that it may be less structured environments that reduce educational investment.