Given the current demands of Swedish vocational education and the withdrawal of the requirement for formal teacher competence in vocational subject teachers, the aim of this article is to develop knowledge of what it means to be a vocational subject teacher in an upper secondary school, i.e. how vocational subject teachers describe their vocational teacher identity. Drawing on a sociocultural perspective, this study analysed data from 22 interviews. The vocational subject teachers describe their relationship with students and the fostering work of teaching for studies, life and work as distinctive characteristics of vocational teacher identity. The fostering work is focused on students' behaviour, i.e. the relational and normative aspects of a social practice. The study results suggest that the identity of vocational teachers includes guiding students towards memberships in various social practices. The benefit of both high-quality teacher competence and vocational competence in vocational teachers is discussed.