Background While evidence on the cost of mental illness is growing, little is known about the cost-effectiveness of programmes in the areas of mental health promotion (MHP) and mental disorder prevention (MDP). The paper aims at identifying and assessing economic evaluations in both these areas to support evidence based prioritisation of resource allocation. Methods A systematic review of health and non health related bibliographic databases, complemented by a hand search of key journals and analysis of grey literature has been carried out. Study characteristics and results were qualitatively summarised. Economic evaluations of programmes that address mental health outcome parameters directly, those that address relevant risk factors of mental illness, as well as suicide prevention interventions were included, while evaluations of drug therapies were excluded. Results 14 studies fulfilled the inclusion criteria. They varied in terms of topic addressed, intervention used and study quality. Robust evidence on cost-effectiveness is still limited to a very small number of interventions with restricted scope for generalisability and transferability. The most favourable results are related to early childhood development programmes. Conclusion Prioritisation between MHP and MDP interventions requires more country and population-specific economic evaluations. There is also scope to retrospectively add economic analyses to existing effectiveness studies. The nature of promotion and prevention suggests that innovative approaches to economic evaluation that augment this with information on the challenges of implementation and uptake of interventions need further development.