In Norway, upper-secondary school admissions in cities are primarily based on grades, favouring students with top grades for the most popular schools. This study examines student support for this grade-based system, exploring gender differences and the influence of family affluence and student grades on attitudes. The findings reveal that boys are significantly more likely to support grade-based admissions, even after accounting for various background factors. Conversely, girls are more likely to favour a system where admission chances are equal regardless of grades. Boys generally have lower grades than girls, suggesting that these preferences are not solely driven by self-interest. The gender gap in support is substantial across the grade spectrum but slightly narrows among top-grade students and those from affluent families, indicating that class and gender might interact. These results align with broader research on gender differences in political attitudes among youth, highlighting the role of childhood socialization.