In this article, we analyse how the share of immigrant children in the classroom affects the educational attainment of native Dutch children. Our analysis uses data from various sources, which allow us to characterise educational attainment in terms of reading literacy, mathematical skills and science skills. Our results suggest that Dutch students face a worse learning environment when they are studying with more immigrant students in the classroom. However, we do not find strong evidence of negative spill-over effects from the presence of immigrant children on the academic performance of the native Dutch students.