In order to promote effective pedagogical practices for students' work-based learning, we need to understand better how students' learning at work can be supported. This paper examines the factors explaining students' workplace learning (WPL) outcomes, addressing three aspects: (1) student-related individual factors, (2) social and structural features of workplace and (3) educational practices related to the organising of WPL periods. The data were collected from final-year vocational students (N?=?3106, n?=?1603) via an Internet questionnaire. The findings from regression analysis showed that students' WPL outcomes cannot be seen merely as consequences of student-related individual factors such as motivation, as has often been suggested; even more important for the success of students' WPL were the social features of the workplace and the pedagogical arrangements for WPL periods. A further finding was that the learning environments of different vocational fields at the interface of school and working life seem to differ significantly from each other, and to offer students different settings for learning at work. This implies that when studies on WPL and professional development are conducted on a single employee group, they should not be directly generalised across different domains.