This article investigates whether attending a high school that offers a specialized science, technology, engineering, and/or mathematics program (high school with a STEM program) boosts the number of students majoring in STEM when they are in college. We use a longitudinal sample of students in North Carolina, whom we follow from middle school through college graduation, to estimate the effect of attending a high school with a STEM program on students' interest in STEM, odds of declaring, and chances of persisting in their intention to major in STEM. Although our multilevel models indicate that attending a high school with a STEM program has a positive association with students' STEM-related outcomes, once we control for sample self-selection through propensity score matching, we do not find evidence that attending high schools with a math and science-focused program significantly influences trajectories of STEM educational advantage for public school students in North Carolina. Our study concludes that perhaps even more important for college STEM success than what happens "in high school" is what STEM-related academic, familial, and formal/informal learning experiences the student had "prior to entering high school".