This article sought to carry out the epistemic examination ofNigeria-Biafra War through the framework of St. Thomas Aquinas' Just War Theory. Nigeria-Biafra War (July 6, 1967 – January 15, 1970) is a genocidal war thatviolated the ethics of war which led to the mass starvation and death of about more than two million Biafra civilians.Thus, this work is geared to evaluate Nigeria-Biafra War in the light of Saint Thomas Aquinas' Just War Theory. This work makes useof analytical method. Saint Thomas Aquinas' just war theory encapsulates the three primary tenetsof just war tradition. His just war theory is codified in Geneva and Hague conventions which laid the ethical foundation of war in international law.Hence, Saint Thomas Aquinas' just war theory has great relevant implications on Biafra war. Biafra war is a genocidal war of defence geared to safeguard the life of the easterners especially the Igbos in Nigeria. His just war theory establishes the rationale for nations to wage war of self defence of people's life or territory. Thus, this work postulates that the principle of jus post bellum is to be implementedin orderto undo the injustice meted out to the Igbos during and after the civil war.
Keywords: aquinas, critical, examination, nigeria-biafra, theory, thomas, vis-à-vis, war