This study critically examines the philosophical foundations of peace frameworks in Africa, contrasting the epistemological and ethical assumptions of Cartesian rationalism with the relational moral ontology of Ubuntu ethics. Cartesian-derived peace paradigms, grounded in abstract reason, individual autonomy, and procedural justice, have shaped liberal peacebuilding approaches but often fail to address the moral and relational dimensions of conflict. Ubuntu, emphasizes interdependence, communal responsibility, and moral repair, providing an ethically robust and culturally resonant framework for peace. This paper explores three objectives: (1) the epistemic and moral limitations of Cartesian rationalism in peacebuilding, (2) Ubuntu as a relational moral ontology capable of sustaining social cohesion and reconciliation, and (3) the operationalization of Ubuntu principles into practical peace frameworks in African contexts. By integrating philosophical critique, normative analysis, and empirical insights, this study proposes a pluralistic, dialogical model of peace that bridges moral theory with institutional practice.