Purpose - The purpose of this paper is to investigate the relationship between pre-training competencies of apprentices and their productivity at the workplace. Design/methodology/approach - For the analysis, the authors use firm-level data on apprentices' oral and writing competencies and competencies in basic mathematics, information technology and problem solving. The authors regress the apprentices' productivity on these school competencies and include a number of firm and apprentice-specific control variables. By reducing the authors' data set to firms that only have one apprentice the authors transform the firm-level data into quasi individuallevel data. Findings - The main findings are that not all competencies are equally related to productivity. Problem-solving competencies followed by oral and writing competencies show the strongest relation to the productive potential of apprentices. IT competencies are also positively but weakly related to the apprentices' productivity. In contrast, higher levels of basic mathematical competencies leave productivity levels largely unchanged. Differentiating between occupational groups, the authors find that the positive relation between the competencies and productivity predominantly exists in commercial occupations rather than in industrial and technical occupations. Practical implications - The results show that better school competencies are associated with a higher productivity of apprentices, which in turn lowers the firms' training costs. From a policy perspective, this finding is important because it implies that, by improving the apprentices' competencies, the firms' willingness to participate in the apprenticeship system can be increased. Moreover, the results are important for training firms because they show on which competencies firms should focus in their recruitment decision. Originality/value - The paper studies for the first time the relation between pre-training competencies and productivity of apprentices at the working place. A practical implication from the authors' analysis is that it could be useful to implement tools measuring the problem solving and oral and writing competencies of apprenticeship applicants in the process of recruitment.