This study utilizes longitudinal data from two 10th-grade student cohorts in Chile to investigate the effects of selective secondary schools. Employing propensity scores and difference-in-difference methods, we find significant and positive short-term effects, ranging from 0.2 to 0.3 SD, with minor variations across subjects and cohorts studied. Likewise, these schools are not a viable alternative for vulnerable students, even though the greatest measured effect is on students with lower socioeconomic status. Our findings suggest that the additional value of selective schools may not be directly linked to standardized test performance but rather related to the interactions among equally talented students.