We estimate the effect that six types of high school math courses have on students' earnings nearly a decade after graduation. We use High School and Beyond transcript data to differentiate courses at a more detailed level than in previous research. This enables us to show that more-advanced courses have larger effects than less-advanced ones. We also provide evidence that math courses can help close the earnings gap between students from low-income and middle-income families. Finally, by incorporating other academic subjects, we demonstrate how specific course combinations can explain the earnings premium related to an additional year of school.