Background/Context: As opportunities for public and private single-sex education have expanded, the debate surrounding this issue has become more heated. Recent reviews of research on single-sex education have concluded that the evidence is mixed, due in large part to the difficulty of attributing differences between single-sex and coeducational students specifically to the single-sex nature of their experience, as opposed to other differences between single-sex and coeducational schools and their attendees. This study comes at a time of renewed national interest in the value and appropriateness of single-sex education, especially as changes to Title IX have expanded the opportunities to establish single-sex classes and activities, and contributes new data with a focus exclusively on the academic engagement of female students from single-sex and coeducational high schools. Purpose/Objective/Research Question/Focus of Study: This study addresses whether levels of academic engagement differ between single-sex and coeducational settings. Research Design: The study uses self-reported survey data and multilevel modeling to address secondary school-level effects in a national sample of women entering college. Findings/Results: The analyses suggest that attendance at a single-sex high school remains a significant predictor of academic engagement even after controlling for the confounding role of student background characteristics, school-level features, and peer contexts within each school. Specifically, women attending all-girls high schools report higher levels of academic engagement across numerous fronts: studying individually or in groups, interacting with teachers, tutoring other students, and getting involved in student organizations. However, these results may also be attributed to other features that differentiate single-sex from coeducational schools, such as smaller enrollments and racial/ethnic diversity of the schools in this study. Conclusions/Recommendations: Although the results of this study support the claims that all-female environments provide a unique opportunity for young women to thrive, these results should be interpreted with some caution. Because of the limitations of the study, it is difficult to make definitive inferences about the relationship between single-sex education and academic engagement, and we cannot assert with confidence that school gender alone is responsible for higher academic engagement. The study points the way for future research that further distinguishes the role of individual and school-level attributes and ideally examines this issue using longitudinal data. Finally, given the current expansion of single-sex education in the public schools, future research ought to employ these methodological advances in studies on single-sex public education and should consider the consequences of single-sex settings for both female and male students.