This study investigated the utility of the Youth Risk Behavior Survey (YRBS) to document associations between homeless status and weight while estimating the prevalence of youth homelessness in three regions. A school-based survey, the YRBS includes youths who have been difficult to involve in past research. Analysis of 2011 YRBS data produced populationweighted estimates of youth homelessness prevalence separately for Connecticut, Delaware, and Philadelphia. Public high school students anonymously reported their housing status, height, and weight on the YRBS. Height and weight were converted to body mass index (BMI) percentile-for-age scores. Homelessness was associated with higher BMI percentile scores for youths compared with nonhomeless peers. Associations between BMI percentile and different forms of homelessness (homeless with family, unaccompanied homeless without family) were explored at each site. Estimates of one-month homelessness prevalence ranged from 3.9 percent to 5.9 percent at each site. Homelessness, especially family homelessness, is associated with risk for higher BMI. The YRBS is an informative tool for estimating the prevalence of youth homelessness, expanding on what is known through other, more commonly used methods.