To help educators make informed decisions about English language learners (ELLs), this Connecting Research to Practice brief provides an overview of key research findings, highlights federal policies related to ELLs, outlines district-level and school-level action opportunities, and lists resources that offer more information. English language learners, as defined by the federal government in the No Child Left Behind (NCLB) Act of 2001, are students 3-21 years old who are enrolled in elementary or secondary school but who do not speak, read, write, or understand English well enough to either (1) reach a proficient level on state achievement tests; (2) be successful in a classroom in which English is the language of instruction, or (3) fully participate in society. Throughout the last decade, while the overall school population has grown by less than 3 percent, the number of ELLs has increased by more than 60 percent. Lists of related resources are included. (Contains 2 figures.)