Although national self-determination emerged as an international legal norm with the formation of the United Nations (UN) in 1945, its implementation continued to be resisted by European colonial powers for decades after. This raises the following question: how was European colonial rule challenged at the UN? This article contends that existing accounts of decolonization have not fully theorized the processes through which colonialism was contested at the UN. It fills this gap by demonstrating the critical role of argumentation, narrativization and discursive struggles through deploying the crucial “Question of Algeria” that was debated between 1955 and 1961. It demonstrates that the Algerian question yielded two opposing discourses—an anticolonial internationalist discourse and a metrocentric civilizational discourse—with both drawing on distinct ideas about human rights and development. The analysis explains the eventual triumph of the former as states increasingly rallied behind the Algerian cause.