There is an enormous inequity in global health as well as research. Less than 10% of research funds are spent on the diseases that account for 90% of the global disease burden. This case study of north-south, south-south collaborations in Sri Lanka is a classic example of the issues faced by mental health researchers in low and middle income countries (LMICs). In this paper, work carried out by the Institute of Psychiatry (IoP), King's College London and the Institute for Research and Development (IRD) partnership since 1997 in Sri Lanka is presented to show an example of a successful private research institution based in a LMIC as a product of south-south and north-south collaboration in mental health research. The evidence of scarcity of mental health research and resources is overwhelmingly abundant in the context of Sri Lanka. IRD-IoP partnership showcases a successful north-south partnership with equality and efficiency. It has moved beyond start-up phase and has become a sustainable initiative in terms of funding, collaboration, research output and policy impact. International funding agencies, academics, and other bodies need to address sustaining such initiatives as priorities in reducing scarcity and inequity in mental health research in developing countries.