Providing instruction in multiple languages has the potential to simultaneously help both native English speakers and English learners to develop language proficiency. "Dual language programs" can help native English speakers develop proficiency in a second language and English learners develop proficiency in both their native language and English. Typically in "dual language programs," classroom teachers instruct students from an early age and over multiple years in both English and a second language called the partner language. These programs vary widely by partner language, primary language of the student population, and duration. Because reaching proficiency in a second language may require substantial exposure over an extended period of time, this report examines "dual language programs" that (1) span at least the elementary grades; and (2) provide at least 50 percent of instruction in the partner language. The What Works Clearinghouse (WWC) reviews existing research on educational interventions to identify evidence-based programs and practices. This Intervention Brief provides an overview of the full Intervention Report. [For the Intervention Report, see ED625372.]