This paper develops a social realist critique of competency-based training (CBT) by drawing on the philosophy of critical realism and the sociology of Basil Bernstein as complementary modes of analysis. CBT is the mandated model of curriculum in the vocational education and training (VET) sector in Australia. It results in an impoverished education that disenfranchises students from access to the knowledge they need to participate in 'society's conversation' and in debates within their occupational field of practice. The paper argues that the relationship between constructivism and instrumentalism structured the development of CBT, even though they are distinct theoretical approaches to curriculum. Constructivist discourses around student-centred learning, situated learning and the contextualised nature of knowledge were appropriated and reworked through the prism of instrumentalism, thereby contributing to the justification and legitimation of CBT, but also to its continuing theorisation and development. The synergies between constructivism and instrumentalism arise because both are committed to the experiential within the contextual as the source of knowledge and this provides the scope for instrumentalism to plunder constructivism. Both emphasise the contextual, situated and problem-oriented nature of knowledge creation and learning and curriculum based on 'authentic' learning in the workplace.