From the abstract: This study examined teachers’ adherence to the language of instruction in dual language education (DLE) programs among teachers in 19 kindergarten through 3rd grade Spanish-English two-way DLE immersion classrooms (n = 5, 90/10 model; n = 14, 50/50 model). Teachers were observed toward the beginning and end of the school year to determine adherence rates of teacher talk by role, teacher talk by purpose, and teacher redirections of students not speaking the target language. Adherence for teacher talk was high across the school year but was lower for assistant teachers compared to lead teachers. Adherence for instructional talk and behavior management talk was also high, though rates were lower for behavior management talk in the fall for the 90/10 model. Redirections of students not speaking the target language were highest in the fall but negligible in the spring during English whole group instruction in the 50/50 model, and redirections were low but increased over time for teachers providing Spanish instruction. Redirection rates were especially low during small group or individual work time. Implications for future research and considerations for supporting teachers’ adherence to the language of instruction are discussed, including accounting for practices (e.g., translanguaging) reflecting updated views about language separation.