<p>While vocational education and training (VET) students in Finland are increasingly multilingual, vocational assessments are often conducted orally in the majority language. This article explores how the de facto language policy was negotiated in two migrant students’ vocational assessment events in Finnish VET. Ethnographic data were collected in two VET institutes from two students, one in catering services and one in surface treatment technology. This nexus-analytical study found that in the students’ assessment the de facto language policy valorized the majority language, which was constructed as an inherent part of both vocational work and the oral assessment event. The monolingual assessment discussion favored the migrant student who was better able to use discursive strategies, such as talking about his practical work, displaying confidence, and making jokes in the majority language, whereas the other student, who had fewer strategies, remained a more peripheral participant. Language per se was erased from the vocational work and assessment criteria. These findings suggest that interactional practices play a role in oral de facto language policy negotiations and can affect assessment, particularly when the de jure policy leaves language unnoticed. Assessment practices aimed at assessing vocational competence carry a majority language component that merits closer consideration to better ensure assessment validity.</p>