This report presents exploratory impact findings for 3-year-olds from the Head Start CARES (“Classroom-based Approaches and Resources for Emotion and Social skill promotion”) demonstration. Head Start CARES is a national demonstration that tests the effectiveness of three program enhancements designed to improve preschool children's social-emotional competence. This report describes the impacts of the three enhancements on social and emotional competencies among 3-year-olds in mixed-age classrooms, which include both 3- and 4-year-olds. Because of uncertainty about whether and how these enhancements might affect 3-year-olds, Head Start CARES was not explicitly designed to test enhancement impacts on this age group. Given the lack of strong hypotheses and limitations in the analysis design for the 3-year-olds, the questions addressed in this report are considered exploratory. The findings presented in this report suggest that the benefits of these social-emotional enhancements can extend to 3-year-olds in mixed-age Head Start classrooms. This report also discusses the need for future research to confirm the results and to better understand how these benefits are generated.