["Developmental Science, Volume 29, Issue 4, July 2026. ", "\nABSTRACT\n\nSocioeconomic status (SES) is associated with adolescents’ cognitive and academic outcomes, yet most research has focused on household SES in high‐income countries. This study examined linear and canonical associations between family‐ and school‐level disadvantage and cognitive‐academic performance in 1296 Chilean adolescents (aged 10–14). Linear mixed models estimated associations between SES and continuous cognitive and academic scores, while canonical correlation analysis (CCA) characterized multivariate SES–cognition–achievement patterns. Findings showed that attending schools with a mid‐ or low School Vulnerability Index (SVI) was associated with higher scores in memory and problem solving (β = 4.3–7.4), whereas SVI was not related to grades; in contrast, parental university education and higher household income were linked to higher cognitive scores (β = 2.9–5.0) and better grades across subjects (β = 0.12–0.45). CCA identified two globally significant covariation modes. The first mode (r = 0.40) captured a broad socioeconomic dimension, driven primarily by family income and parental education, which correlated with generalized cognitive and academic performance. A second mode (r = 0.25) captured secondary variance in selected academic subjects and inhibitory control. However, individual SES indicators did not reach statistical significance on this component. These findings suggest a shared socioeconomic gradient driven predominantly by family resources underlies adolescent cognitive and academic outcomes. Alongside this global trend, school vulnerability is primarily linked to specific cognitive functions and family socioeconomic status is pervasively associated with academic achievement. Mitigating educational disparities would therefore benefit from multi‐level policies targeting both environments.\n\n\nSummary\n\nA shared socioeconomic gradient driven by family resources underlies adolescent cognitive and academic outcomes.\nSchool vulnerability associates specifically with targeted cognitive functions.\nFamily socioeconomic status pervasively associates with broad academic achievement.\nEffective mitigation of educational disparities involves targeting both home and school contexts.\n\n\n"]