The aim of this paper is to understand the ‘theory of change’ underlying interventions to support vocationalisation of general education as well as vocational education and training (VET) and skills development. The focus is on interventions supported by development agencies and donors, although national policies are also considered, as the agencies work with governments and are both guided by, and influence, their priorities. The first aim is to interrogate what problem VET is seen as the answer to, and how VET is seen to solve that problem (their theory of change). The second aim is to understand the extent to which, and ways in which, vocationalising education is supported and VET favoured, as compared to other components of the education system such as early childhood development, early primary education, or university expansion, as an educational intervention.   We found that while some organisations have explicit theories of change—generally multiple theories of change addressing different aspects of the overarching system—many are currently in the process of developing these theories of change. A few state that they do not have a theory of change but rather focus on the development of targets for different components of the system.