Homelessness is a pervasive problem among youth aging out of the foster care system. Many of these youth exit the system without any concrete plans for their future and wind up suffering bouts of homelessness. Although a growing body of literature has begun to look at the factors that contribute to homelessness among this population, less has been written about the factors that guard against homelessness. Furthermore, most of the studies have been confined to a particular geographic area. Using data from the National Youth in Transition Database (NYTD), combined with the Adoption and Foster Care Analysis Reporting System (AFCARS), the present study provides an analysis of the risk and protective factors contributing to homelessness among a nationwide sample of foster care youth at age 21, 29% of whom had experienced homelessness. The findings indicate that the strongest protective factors against homelessness were having a connection to an adult and remaining in foster care until age 21. Other protective factors included having at least a high school education, being currently enrolled in school, and having a full-time job. On the other hand, the strongest risk factors contributing to homelessness were having been incarcerated, as well as having been referred for substance abuse. Other significant risk factors were having a runaway history, having received public food assistance, and being emotionally disturbed. Given these findings, child welfare agencies should make greater efforts to ensure that youth have an adult in their life whom they can trust and turn to for help, as well as encourage youth to remain in care until they are better prepared for life on their own.