Since the early 1980s, the Middle Drâa Valley (MDV) in south-eastern Morocco has seen agricultural expansion from oases into customary land owned by different tribes, creating the potential for conflict. Customary land conflicts are often depicted as obstacles to socioeconomic development. This article analyses the drivers of land conflict between the Mssoufa and Kaaba tribes, explaining how the conflict restructures power and authority relations to control resource access. We use an actor-based approach and access theory to analyse data from observations and 34 semi-structured interviews conducted between May and July 2021 and September and November 2022. Interviewees included members of the conflicting tribes, government representatives, and private sector actors. The conflict stems from unequal land access between tribes, rooted in historical power reconfigurations influenced by droughts, market dynamics, national agrarian development policies, and changes in customary land access rules. We argue that preventing further escalation of intertribal land conflicts in the MDV requires directing the actors’ motivations and capabilities towards cooperation and resource sharing by implementing a third-party intervention model of conflict resolution in combination with a structural peacebuilding approach. Additionally, we discuss the implications of our findings for promoting sustainable development in the MDV, particularly focusing on Sustainable Development Goal (SDG) 16: Peace, Justice, and Strong Institutions, while also identifying implications for SDGs 1, 10, and 13.