Preschool teachers can best educate youngsters learning their home language and English by using children's primary language where possible, adopting effective practices for building English language skills, and involving families in supporting children's learning. This article surveys the growing body of research on improving preschool Dual Language Learners' (DLL) educational opportunities to help inform educators responsible for creating settings for young DLLs. This review of the research is organized around four key topics: (1) Employing children's home language in the early childhood curriculum; (2) Comparing effective practices for DLLs and English speakers in English-only programs; (3) Promoting language development in English and the home language; and (4) Involving families in supporting children's language learning. (Contains 27 endnotes and 1 footnote.)