Compared to rival ideologies, liberalism has fared rather poorly in modern Iran. This is all the more remarkable given the essentially liberal substance of various social and political struggles – for liberal legality, individual rights and freedoms, and pluralism – in the century-long period since the demise of the Qajar dynasty and the subsequent transformation of the country into a modern nation-state. The deeply felt but largely invisible purchase of liberal political ideas in Iran challenges us to think more expansively about the trajectory of various intellectual developments since the emergence of a movement for reform and constitutionalism in the late nineteenth century. It complicates parsimonious accounts of Shi'ism, secularism, socialism, nationalism, and royalism as defining or representative ideologies of particular eras. Hidden Liberalism offers a critical examination of the reasons behind liberalism's invisible yet influential status, and its attendant ethical quandaries, in Iranian political and intellectual discourses.