Years of experience, education level, and subject matter expertise are three measures of teacher qualification that are employed widely in contemporary educational policies including tenure, salary, and hiring, despite significant questions about their effectiveness at predicting student performance. These questions reveal a critical gap in the literature, concerning, in particular, the enduring impact of teachers' qualifications on students' educational experiences, and they ways in which related research has traditionally been framed and conducted. Specifically, studies examining these predictors have focused almost exclusively on investigating the role that an individual teacher's qualifications have on students' performance. In schools, however, students are exposed to different teachers every year, and those teachers often have differing qualifications. This study explores the impact of teacher qualification from a cumulative perspective by examining the relationship between cumulative science teachers' qualifications (measured by years of experience, education level, and subject matter expertise) and students' educational success (academic achievement, college enrollment, and decision to major in a Science, Technology, Engineering, or Mathematics field). The study found that students taught by science teachers who--as a group--were cumulatively more highly qualified, tended to have higher achievement, as well as better educational pathways and outcomes in STEM. Given that students are taught by teachers from across a broad spectrum of qualification throughout their schooling, findings from this study could have important implications, not only for research and practice, but also for education policy.