This study examines how vocational teachers in the hairdressing programme manage assessment in relation to work-based learning (WBL), and how their scope for action is enabled and constrained when WBL documentation is used as part of the grading process. The study takes a qualitative approach and is based on semi-structured interviews with ten hairdressing teachers from three upper secondary schools. The material was analysed through thematic analysis, guided by the theory of practice architectures. The results indicate that hairdressing teachers’ assessment practices are shaped through three interconnected projects: a working-life project, a fairness project and a teacher project. The working-life project shows how norms of service, customer interaction and employability shape what is interpreted as central vocational knowledge. The fairness project demonstrates a recurring difficulty in that supervisors’ assessments tend to be general in nature and predominantly positive and that teachers rarely receive critical observations, as such information is perceived as sensitive. The teacher project shows how assessment is influenced by limited time, few opportunities for WBL visits and documentation that is difficult to rely on because it often provides limited information. The study contributes to previous research by showing how insufficient supervisor assessments are connected to professional language, documentation practices and relationships between supervisors, students and teachers. It also highlights a tension in which teachers, in practice, communicate to students that work-based learning is included in the final grade, while lacking clear formal support for how this should be done within the regulatory framework. Assessment therefore emerges as a practice shaped not only by the teacher’s professional judgement, but also by cultural-discursive, material-economic and social-political conditions beyond the individual teacher’s control.