The number of students with special educational needs (SEN) is growing rapidly. This study compared the correlations between the share of students identified with SEN and student diversity (socioeconomic status and ethnicity) at the school level in three countries. We used the principal questionnaire from the 2018 Teaching and Learning International Survey (TALIS) to examine data from principals in three welfare states (the United Kingdom, France, and Sweden) and whether minority students in these three countries also receive special education. We conducted an ordinal regression analysis to examine the data. First, our results suggest that the share of immigrants in schools does not reliably predict the share of students placed in SEN. Second, the schools' share of refugees predicts the share of students placed in SEN, although the results vary by educational stage and country. Third, the schools' share of socioeconomically disadvantaged students predicts the share of students with SEN in all countries. We conclude that our study both agrees and disagrees with overrepresentation theory and equity theory. Finally, we suggest that welfare state theory may explain these differences.