The changing demographics of the United States and recent focus on educational standards have made it increasingly critical to address the needs of the many linguistically and culturally diverse students in our schools. Schools throughout the United States are attempting to meet the needs of this diverse population through a wide variety of programs. This chapter describes some of these various programs, explains learning theories related to how a second language is learned as well as the “language” of science, and lastly, it provides some suggestions for best practice in science teaching and language teaching.