Previous research on housing problems has concentrated on the more visible homelessness rather than more intermediate forms of housing problems such as doubled-up housing. This article expands this research by analyzing entrance into doubled-up housing among a sample of adolescents. This common type of vulnerable housing has been linked to various social and psychological problems. It commonly precedes homelessness, and it potentially increases the risk of homelessness. We find that doubled-up housing frequently occurs during young adulthood and is predicted by insufficient human capital, broken social ties, and personal disabilities.