Increasing the number of students who study science and math is a priority in many countries, but between-school inequalities in the opportunity to learn these subjects is not well understood. We examine stratified opportunities to learn science and math subjects in upper secondary schools in Australia, as a case study for developing a theoretical framework about access to curricular subjects in comprehensive education systems. We found that biology and chemistry are offered in most schools but substantial inequalities exist in access to physics and especially advanced mathematics. School size, school socioeconomic composition, school sector and school location (rural/urban) predict whether a school offers advanced mathematics. The findings suggest that access to science and math subjects is far from universal even in a prosperous country with a comprehensive secondary education system. We conclude by presenting a theoretical framework for guiding future research about the factors that shape between-school curricular inequalities.