Research on inequality and high schools often focuses on inequality "within" and "between" high schools. Different high schools may have markedly different access to resources such as college counselors and Advanced Placement offerings, or inequality may exist within a high school due to tracking or other forms of stratification (Engberg & Wolniak, 2010; McDonough, 1997; Solórzano & Ornelas, 2002). Less known is how high schools may influence differential access to resources "outside" of school that can influence postsecondary pathways. Naturally, high school plays a central role in a student's educational experience, but it is also part of a broader ecosystem that includes students' families, community, neighborhood, and supplementary educational resources. One supplementary educational resource that is popular within certain communities is SAT or ACT preparation (hereafter abbreviated as "SAT prep"), which generally takes the form of SAT classes, tutors, or books. The SAT (formerly the "Scholastic Aptitude Test," now known as just the SAT) plays a critical gatekeeper role in the college admissions process, given that SAT or ACT scores are required for most institutions that are not open access (Briggs, 2009). However, students often enter the test with widely differing levels of exposure to the test. While previous studies have examined how individual students' characteristics are associated with SAT prep (for instance, that wealthier students are more likely to take SAT prep), research has focused less on the role of the high school environment and how it might inform participation in SAT prep. Instead of viewing the two realms as distinct, this study seeks to investigate the link between school-based and out of school-based resources. It also adds to knowledge of how high schools influence the stratification of educational opportunity. Lastly, it extends the research on SAT prep to examine influences beyond individual students' attributes (e.g., race/ethnicity, parental education) and into the institutional contexts that they inhabit; further, it clarifies whether the relationship between individual-level variables (race/ethnicity, income) persist when high school contexts are controlled for, and how these patterns may vary between groups.