Disparities between males and females in attitudes toward science have been the focus of extensive investigations. Studies have found that females feel intimidated by their male peers in science and mathematics classes, making girls less likely to participate. Their confidence in these areas decreases and they become less likely to follow related career paths. Researchers and educators are at task to find methods to provide equal learning opportunities for all students. The purpose of this action research was to investigate the effects of single-gender grouping and inquiry-based teaching on girls' participation and attitude in science class. This study took place in a second grade classroom at a suburban school in the fall of 2005. Surveys and interviews were used to investigate students' attitudes before and after working with inquiry learning single-gender groups. Using observations, female students' participation was recorded according to the kind of participation they exhibited – passive/assisting, active/leading, or active/manipulating. Students maintained journals to record their understanding of science content and rated the lessons. In addition to improving female students' attitudes towards science, inquiry learning fostered an increase in active student participation. Six out of the eight female students perceived that girls participated more in single-gender groups during the study than they did before the study in their regular mixed-gender groups. However, they did not report a change in their own participation in relation to their peers after working in single-gender groups. Further research with control groups was suggested with a larger and more socio-economically diverse population.