<p>This article offers a corrective to the narrow-mindedness of mainstream economics by critically examining how leading schools have treated and often dismissed the question of involuntary unemployment. Its central contribution lies in restoring involuntary unemployment to the analytical foreground through a comparative assessment that spans Classical, Walrasian, New Classical, New Keynesian, Keynesian, and Marxian–Kaleckian perspectives. The analysis demonstrates that while Classical, Walrasian, and New Classical frameworks seek to render the concept theoretically irrelevant, Marxian–Kaleckian approaches preserve and deepen its significance. New Keynesian economics, although formally retaining the concept, is shown to dilute the core insights of Keynes’s original analysis by reabsorbing unemployment into market-clearing logic. By mapping these divergent theoretical trajectories, the article highlights the rich yet neglected legacy surrounding involuntary unemployment. It argues that reintroducing these debates into teaching, research, and policy analysis is essential not only for understanding unemployment as an inherent feature of capitalist society but also for expanding the analytical boundaries of the economics discipline itself.</p>