The extant academic literature in the field of regional International Relations has paid little attention to non-state actors’ organizational relations in building region-ness. Yet, the region offers sets of organizational relations outside, alongside, and as part of the formal regional state structures to do with gender, which offer insights into non-state regional relations and thus help to fill the lacunae in the field and facilitate understanding of the regional dynamic of international relations. This article examines how organizational relations of non-state actors in gender security play out in the Southern African Development Community (SADC) region. It highlights the shortcomings of the inter-governmental approach to international relations pursued by various scholars. Drawing on interviews with representatives of NGOs, governments, the SADC, and annual reports, as well as the academic literature, it argues for a socio-historical approach to understanding regional organization and transnationalism, which considers African agency in building region-ness.