Dutch mainstream education is a selective school system. Students are selected for different ability tracks at the age of 12. They are grouped to perform at the same level in all subjects, even though the students differ significantly in proficiency in mathematics and languages. Analysis of the streaming of 598 students in the first years of secondary education shows that, compared to other students, significantly more one-side-talented students with proficiency in either mathematics or languages attended the lowest ability level. In life-world interviews, ten former students with high proficiency in either mathematics or language, reflected on their school careers and crucial time moments during their school career. They report that they did not experience these moments as disappointing. Even so, following the lower ability track was not a solution to their problems as their stronger domains were not sufficiently challenged. Future research should focus on how students' different proficiencies can be addressed and further developed within the ability tracking system of Dutch secondary education.