Drawing on public opinion data on Korean adolescents’ perception on the socially disadvantaged collected in 2018 by the Center for Social Cohesion Education, we examined the structural relationships between socio-economic background, social capital in the family and at school, academic achievement, meritocratic attitudes, caring attitudes towards the socially disadvantaged, and attitudes toward affirmative action in college admissions among high school students using the structural equation modeling. Our SEM results exhibited that socio-economic background has little impact on attitudes toward affirmative action in college admissions. In contrast, academic achievement, meritocratic attitudes, and the caring attitudes towards the socially disadvantaged are found to have a direct effect on attitudes toward affirmative action. While trust in teachers, peer relationships, and parent-child relationships, which represent social capital in the family or at school, do not have a direct effect on attitudes toward affirmative action, they all prove to exert an indirect effect on attitudes toward affirmative action via the caring attitudes towards the socially disadvantaged. Based on the major findings, we discussed briefly implications and policy suggestions that can enhance attitudes toward affirmative action in college admissions.