The growing importance to finding workable solutions to the problem of unsustainable and inefficient resource use cannot be overstated.  In the world facing one of its critical sustainability periods, efficient resource utilization to ensure sustainable development is a problem policymakers should grapple with at a loc, regional and local levels. Because of this, the Water-Energy-Food-Ecosystem (WEFE) nexus has seen a growing number of proponents and supporters worldwide.  This thesis examines the WEFE nexus and its relevance for sustainable resource management, focusing on South Africa’s Inkomati-Usuthu Water Management Area (IUWMA).  WEFE nexus criticizes existing sector-based approaches for their limited recognition of cross-sectoral linkages.  This thesis presents a systematic review of the WEFE nexus in the IUWMA, identifying policy gaps and making recommendations to enhance integrated resource and environmental management based on the WEFE nexus approach.  The findings highlight various factors affecting energy generation, agriculture, water quality and quantity, and ecosystem-related factors within the IUWMA.  The thesis also provides an overview of critical policies related to the WEFE nexus in the IUWMA, demonstrating coherence (or lack thereof) and environmental considerations, and international cooperation.  The implementation of the WEFE nexus policy faces opportunities in collaboration but challenges such as institutional barriers, knowledge gaps, and limited political will.  The IUWMA also presents a complicated case owing to its transboundary nature, to which special attention must be paid when considering WEFE nexus approaches.  The discussion emphasizes the need for a holistic WEFE nexus approach to avoid inefficiencies and conflicts and calls for strong governance structures and equitable resource allocation.  Implementing the WEFE nexus approach can foster collaboration, sustainable resource management, land resilience to climate change impacts with political support, regional cooperation, and stakeholder engagement.