Dutch prevocational secondary schools are reforming their educational programmes to make them more competence-based. This reform has substantial implications for the roles played by teachers. Yet, little empirical research has been conducted on teachers' processes of competence development in vocational settings. This study explores teachers' individual action theories regarding the introduction of competence-based prevocational secondary education. The cognitive apprenticeship model provides a conceptual framework for addressing this issue. The research questions addressed here are: How do teachers value elements of the cognitive apprenticeship model in designing and delivering competence-based prevocational secondary education?, and, What individual action theories do teachers have regarding competence-based prevocational secondary education? The study was designed in two phases. In the qualitative phase, interviews and concept map techniques were used, while the quantitative phase employed a questionnaire. Teachers valued elements of the cognitive apprenticeship model differently, and suggested two additional features: a custom-made educational approach and the professionalisation of teachers. (Contains 2 tables and 1 figure.)