In this paper, we attend to increasing calls to analyse how difference on the basis of race is fabricated in mathematics education within the context of transnational mobility. Racialisation is a ubiquitous phenomenon closely related to globalisation which contributes to how the ideal global citizen is being viewed. It occurrs via a wide range of mechanisms, practices, and artefacts. Assuming these elements, we examine the process of racialisation in a Chilean school for adults attended by Black Haitian immigrants. Our analysis reveals the existence of a differential system of school mathematics implemented for Black students that functions as a racialising assemblage which dehumanises this student population. Rather than an empowering tool to access the labour market and secure economic stability, mathematics education may contribute to relegate immigrants to second class citizenship in their host countries.