This paper investigates the role of school quality in human-capital formation. Specifically, I investigate how the timing of school quality differentially affects long-run outcomes. Using individual-level data on the universe of public-school students in California, I estimate elementary-, middle-, and high-school quality using a value-added methodology that accounts for the fact that students sort to schools on observable characteristics. I then determine the impact of school quality on future K-12 and postsecondary outcomes. I find that high-school quality has the largest impact on postsecondary enrollment, while elementary- and middle-school quality play a larger role in college readiness. In other words, early human-capital investments are important for future postsecondary success, but the unique timing of the college decision process allows for later human-capital investments to also play a significant role