"Peer Tutoring and Response Groups" aims to improve the language and achievement of English language learners by pairing or grouping students to work on a task. The students may be grouped by age or ability (English-only, bilingual, or limited English proficient) or the groups may be mixed. Both peer tutoring pairs and peer response groups emphasize peer interaction and discussion to complete a task. Three studies of "Peer Tutoring and Response Groups" met the What Works Clearinghouse (WWC) evidence standards. These studies included 118 English language learners from first to sixth grades in Florida, Texas, and Washington state. No studies that met WWC evidence standards with or without reservations addressed reading achievement or mathematics achievement. The WWC found "Peer Tutoring and Response Groups" to have positive effects on English language development. (Contains 8 tables and 6 footnotes.) [The following studies are reviewed in this intervention report: (1) Jun-Aust, H. (1985, March). "Individual differences in second language learning of Korean immigrant students." Paper presented at the International Conference on Second/Foreign Language Acquisition by Children, Oklahoma City, OK; (2) Prater, D. L., & Bermudez, A. B. (1993). Using peer response groups with limited English proficient writers. "Bilingual Research Journal," 17 (1&2), 99-116; (3) Serrano, C. J. (1987). The effectiveness of cross-level peer involvement in the acquisition of English as a second language by Spanish-speaking migrant children. "Dissertation Abstracts International,' 48(07), 1682A. (UMI No. 8723140).]