This chapter discusses the demographics and educational circumstances of dual-language learners (DLLs) in U.S. schools. It notes that the population of DLLs ages 0-8 has grown rapidly in recent decades to around 2-3 million as a result of increased immigration. DLL students tend to face greater educational risks on average due to factors like low family income, low parent education levels, and ethnic minority status. The chapter reviews different program models that have been demonstrated as effective for enhancing DLL students' development and early academic achievement.