ABSTRACT This article offers the first comprehensive reconstruction of Hannah Arendt's contribution to the venerable chapter of modern intellectual history known as ‘the Idea of the university.’ Arendt first jotted down her thoughts on this topic in a 1946 letter to Karl Jaspers, in response to the manuscript of his then forthcoming book Die Idee der Universität. She later revisited the topic in three different moments. We trace these three sequels back to three contemporary political crises to which she bore witness: (i) the problem of Arab-Jewish relations following the founding of Israel, (ii) the suppression of freedom of speech during the McCarthy era, and (iii) the American student protest movement of the 1960s. At the heart of Arendt's idea of the university is a tension that she never managed to resolve: namely, that between the image of the university as a nonconformist community ethically committed to the transformation of the social world, on the one hand, and the image of the university as a secluded sanctuary of contemplative freedom dedicated to the disinterested pursuit of truth, on the other. Whereas the first puts her at odds with Jaspers and is predominant in the early reflections, the second pulls her closer to him and becomes prominent in the later ones. More broadly, the article contends that the history of Arendt's reflections on the university bears on our understanding of the evolution of her political thought.