We investigate the effects of various measures of science teachers' cognitive skills—based on academic degrees, math matriculation scores, and SAT math scores—on their students’ educational achievements. Utilizing detailed administrative data of 12th grade students and their science teachers, spanning the years 2012 to 2019, we find clear and positive effects of teachers' cognitive abilities on both students' short-term matriculation test scores and several long-term measures of academic success, such as the probability of pursuing post-secondary studies at a research university and the probability of choosing a STEM major subject. Our analysis underscores the relative importance of teachers' mathematical orientation compared to acquired skills in broader general science. Additionally, higher gains from teachers' cognitive abilities are particularly evident among students with stronger aptitude, higher socio-economic backgrounds, and same-gender student-teacher matching.