As learning sites for sustainable development, United Nations Educational, Scientific, and Cultural Organization (UNESCO) Biosphere Reserves (BRs) are unique sites that promote human–nature interactions in biodiversity conservation. BRs are part of a World Network of BRs, which provide opportunities for transnational collaborations. With the 50th anniversary of UNESCO's Man and Biosphere Programme, we systematically analyzed literature on BRs in the Global South and assessed whether transnational connections emerged from the network especially in fulfilling the shared goal of being learning sites for sustainable development. We found little evidence of transnational networking between BRs in the Global South. While there are nonformal environmental education initiatives in BRs, there is a lack of reported transdisciplinary approaches and formal education about BRs in BRs. Furthermore, Indigenous and local knowledge (ILK) is rarely integrated into initiatives. Equitable and inclusive partnerships, integration of ILK, and co-production of knowledge could be enabling factors for transdisciplinary education.