This Toolkit is meant to be a resource for teachers, parents, and administrators involved with two-way immersion (TWI) programs, particularly those at the elementary level. Two-way immersion is a form of dual language instruction that brings together students from two native language groups for language, literacy, and academic content instruction through two languages. In the United States, these two groups are native English language speakers and native speakers of another language, usually Spanish. Because of the integrated nature of the programs and the fact that instruction is provided to all students through both languages, TWI programs allow students to be both language learners and language models for their peers. This Toolkit is composed of three segments that address program design and planning, classroom instruction, and parental involvement, respectively. The classroom instruction segment includes a Question & Answer (Q&A) document on teaching in TWI programs; model lesson plans that show how best practices are implemented in the TWI classroom; a study guide to facilitate the use of the Q&A document and model lessons for professional development; and additional resources on effective instructional practices in TWI programs. The parental involvement segment includes an overview of two-way immersion, a Q&A document that addresses questions and concerns that parents frequently have, a home-school communication template designed to help classroom teachers facilitate strong home-school connections, and additional resources that include suggested readings on parent involvement in two-way immersion programs and links to resources that parents may find useful. All of the parent materials are available in Spanish as well as English. Student Study Team Red Folder Process: Early Intervention for Struggling Students and Identification Process for Students with Learning Differences is appended. A glossary is also included. (Contains 1 table and 1 figure.)