Using a national database, this study examined the relationship between the language of instruction models and the frequency of peer-mediated learning activity on English learners' reading achievement (N = 1,004). Results from the Multilevel Modeling (MLM) analyses revealed an interaction between the language of instruction and the frequency of peer-mediated learning in EL's second-grade reading. Specifically, ELs enrolled in English as a Second Language (ESL) programs who worked weekly with monolingual English speaker peers had greater reading scores than those who worked daily or monthly. Implications and recommendations for future research are discussed.