Assistant teachers play an important role in Head Start and other early care and education (ECE) programs. This study found that assistant teachers contribute to classroom quality in the program's day-to-day implementation. Thirty-eight assistant-lead teaching teams from Head Start preschool classrooms across 14 Head Start centers within the larger agency participated in this study. Dual-language learner (DLL) children were present in each of the 38 classes. The minimum number of DLL children in any class was 3, and the maximum was 20. The report's findings shed light on the everyday contributions Head Start assistant teachers make to classroom quality, measured through teacher-child interactions. Findings have implications for policymakers, education administrators, and practitioners interested in understanding the importance of assistant teachers to the quality of Head Start programming, and particularly their role in supporting the growing population of DLL children in Head Start. The findings have implications for policy development that positively supports practices that train, develop, and retain assistant teachers in the workforce pipelines of Head Start and other ECE settings.