The article draws on Michael Walzer’s just war theory to assess the conduct of the Lebanon War of 1982 (Operation Peace for Galilee) and argues that according to the underpinning principles of Walzer’s theory, it was an unjust war. Sharon’s war plans, codenamed “Grand Oranim,” were designed to relieve the Lebanese Christian militias of their so-called Palestinian burden by driving the refugees into Jordan where they would presumably bring about a regime change and turn Jordan into a Palestinian state. My analysis focuses on the causes of this war, jus ad bellum, whether it was a war of self-defense, and the means that were employed in its conduct, its jus in bello. Likewise explored and analyzed here are the concepts of proportionality and the treatment of non-combatants.