This article explores the African Mental Health Action Group (AMHAG), one of the earliest examples of the World Health Organization’s (WHO) attempts to promote ‘ownership’ over development through the South–South cooperation envisaged in Technical Cooperation in Developing Countries. Formed in 1978, the AMHAG was intended to guide national and regional policy on mental health, while also fostering national and collective self-reliance. For a short period, between the late 1970s and the early 1990s, it was central to the WHO’s strategy for promoting policies of mental health in primary healthcare in Africa. It was a largely ineffective tool, with national governments having different opinions on the value of mental health, and poor coordination between AMHAG countries. Approaching the AMHAG as a regional project and transnational network, however, the article provides explores the importance of regions and regionalism in international health cooperation, as well as the inequities of participation in health development. Drawing on WHO archival material spanning over twenty countries and two national liberation movements, it argues that participating countries were differently positioned not only to navigate relationships between countries, but also to contend with the shifting landscape of international assistance, as well as – for some – contexts of war, violence and political and economic instability. The article not only serves as a case study of power imbalances in a failed development initiative, but also sheds light on the WHO’s engagement with mental health during a period that historians of psychiatry in Africa have tended to overlook.