Subtitle VII-B of the McKinney-Vento Act, recently reauthorized as part of the No Child Left Behind Act, was designed to limit the negative effects of school mobility on students experiencing homelessness. Students may change schools as they move among temporary housing options, leading to lower academic achievement, and emotional and social distress. The Act gives students experiencing homelessness the right to remain in one school. While the Act plays a critical role in preventing homelessness and increasing educational achievement, programs to provide affordable housing and support to struggling families are essential to improving the educational achievement of children and youth experiencing homelessness. The residential transience of students in homeless situations can lead to frequent school changes. This unplanned school mobility can be devastating to a child's or youth's education.1 This article explores the school mobility of children and youth experiencing homelessness and the success of the McKinney-Vento Act in addressing this mobility. It also proposes that affordable housing is the key to eliminating the mobility associated with homelessness and consequently improving the educational achievement of these highly mobile students. THE SCHOOL MOBILITY OF STUDENTS EXPERIENCING HOMELESSNESS: WHAT IT LOOKS LIKE AND WHY IT OCCURS Where would you go if you came home from work one evening to find your furniture, clothing, dishes, books, papers, and all your belongings on the street, and a padlock on your door? Where would you take your children? Family homelessness is primarily caused by a lack of affordable housing combined with low family incomes. Much affordable housing has been converted to condominiums or more expensive units, and neither developers nor the government is taking adequate steps to replace and expand affordable housing. In 1995, there was a national shortage of 4.4 million low-cost housing units (Daskal, 1998), a shortage that continues today. As housing costs have increased, wages for low-income workers have not increased proportionately. A minimum wage job does not provide enough income for a household to afford the Fair Market Rent (FMR)2 for a two-bedroom rental unit anywhere in the United States. The Bureau of Labor Statistics reported that in 2001, over two million workers earned the federal minimum wage or less; over 60% of these workers are family heads or spouses of family heads. In fact, to afford a two-bedroom rental unit at the nationally weighted FMR, a worker would have to earn $14.66 per hour, nearly three times the federal minimum wage (Pitcoff, Schaf fer, Dolbeare, & Crowley, 2002). The combination of high housing costs and low wages forces low-income families to spend a large portion of their incomes on rent. When a family is unable to keep up with household bills, a parent loses a job, an accident or illness occurs, a parent must flee from an abusive partner, or fire or other natural disaster claims a home, the entire family may find itself without shelter. Homelessness, however, does not always involve an entire family. Youth on their own typically become homeless for slightly different reasons. Many flee physical or sexual abuse. A recent study of youth who had run away from or been kicked out of their homes found that over one-third reported sexual abuse and one-half reported physical abuse in the home (MacLean, Embry, & Cauce, 1999). Severe dysfunction in the home is also common. For example, over two-thirds of the youth reported that at least one parent abused drugs or alcohol (MacLean et al., 1999). Some young people are not welcome in their homes, due to their sexual orientation or identity, pregnancy, or other types of family conflict. These young people lack the financial resources to provide for their own housing and other necessities, and often reside on the streets, in shelters, or in other homeless situations. …