Adolescents belonging to minority or marginalized groups often experience discrimination, which may negatively affect their mental and physical health. Using the dataset of the 2018 Health Behaviour in School-Aged Children (HBSC) study, we analyzed perceived discrimination based on various grounds in four minority groups of schoolchildren in Ireland: sexual minority youth, youth living with a disability or chronic condition, immigrant youth, and youth belonging to the Traveller community. To minimize the potential confounding effect of psycho-social contextual factors, we used a case-control matching approach, comparing minority groups with their non-minority peers matched by gender, age group, and social class. Minority groups were significantly more likely than their matched non-minority counterparts to report discrimination, not only on the basis of their minority status but also on other grounds. These associations varied in their effect size. We discuss educational and policy implications of the findings for reducing discrimination and structural stigma in school settings.