Recently, single-sex classes within public coeducational schools have proliferated across the USA; yet, we still know little about whether and how single-sex science classes influence adolescents' attitude and affect toward science. This exploratory study expands upon our current understanding by investigating the extent in which female and male students' enrollment in either single-sex or coeducational science classrooms may influence their academic self-concept in science. Utilizing a quasi-experimental research design, findings suggest that being enrolled in single-sex science classrooms influence how students in this study perceive their abilities to perform and learn in science, particularly for females in single-sex science classrooms.