Mobility, rather than stability, has become the norm for students in schools across the United States. The student mobility rate is now higher in the United States than in any other industrialized country. This Information Capsule discusses the reasons for student mobility and the characteristics of highly mobile students and families. Research studies on the impact of mobility on students' academic achievement and social adjustment and its effect on the entire school community are reviewed. Strategies designed to help schools reduce mobility rates and facilitate students' transitions to new schools are summarized.