Shadow education or private outside-of-school activities for supplementing academic achievement in formal education, has developed and expanded on a global scale in recent years. Since shadow education is linked to students’ academic achievement in many countries, unequal opportunities for shadow education has become a significant problem. Using data from the 2012 Program for International Student Assessment (PISA), this study analyzes whether ability composition of schools attended affects students’ use of shadow education in Korea. The results show that students’ academic achievement is positively correlated with their use of shadow education. In addition, students in higher-achieving schools are more likely to use shadow education. However, the relationship between ability composition of schools and the use of shadow education is not significant when controlling for the socioeconomic composition of schools. Findings suggest that socioeconomic status not only at the individual level but also at the school level matters to shadow education.
