Over the last few years, increasing scholarly and media attention has been paid to the plight of undocumented immigrant college students. However, only a small fraction of undocumented youth actually moves on from high school to postsecondary opportunities. Indeed, the exclusion from financial aid eligibility and low family socioeconomic status severely limit undocumented students' ability to matriculate to institutions of higher learning. But little is known about the ways in which school experiences shape postsecondary outcomes. This article focuses on the high school experiences of a sample of undocumented young adults and examines the ways in which school structures shape access to resources needed for postsecondary matriculation. In doing so, I argue that school-based networks are critical for success. However, these networks are fundamentally shaped by the school structure. This article draws from 78 in-depth life histories of undocumented Latino young adults in the Los Angeles metropolitan area. I incorporate a sample, stratified by educational experiences. The lived experiences of these young adults shed important light on the broader world in which they live and the ways in which immigration policies interact with school practices to shape success and failure. (Contains 8 footnotes.)