Widely published statistics document patterns of disproportionately low achievement and participation in science and mathematics by women, minorities, and the poor. This report examines the distribution of science and mathematics learning opportunities in the nation's elementary and secondary schools. It addresses four key issues: (1) what science and mathematics are being taught to which students, (2) how these subjects are being taught, (3) by whom they are being taught, and (4) under what conditions they are being taught. The findings indicate that low-income, minority, and inner-city students have fewer opportunities to learn science and mathematics. They have considerably less access to science and mathematics knowledge at school, fewer material resources, less-engaging learning activities in their classrooms, and less-qualified teachers. These inequalities are linked to both characteristics of the schools and characteristics of the classrooms.