This thesis compares state formation in the early years of the Indian and Irish states. There are unusual similarities between the first and joint-second states to secede from the British Empire in the twentieth century considering the enormous geographical, political, and cultural gulf between them. Yet the many commonalities between the early Irish and Indian states are notable for the very reason of their widely differing contexts. There has been some academic focus on Irish-Indian connections and comparison in the years leading up to the independence of each, but the historiography mostly falls silent on this topic in the aftermath. This study addresses the following questions from the historian's perspective, though with due attention to the political theory of state-building: how did each state proceed to establish its institutions in the three key areas of 1) taxation, 2) law and order, and 3) the military? And what do the parallels and divergences of these processes signify about postcolonial state formation more broadly? This thesis finds significant analogy between the two states in the first decade or so of independence in all three areas. Twin themes that resurface throughout the work are continuity and centralisation. Institutional continuity between the Raj and independent India was the more readily apparent, but in Ireland too the norms and behaviours of the previous regime were remarkably resilient within new institutions. By contrast it was in the unitary Irish Free State that the centralisation of power in the executive was more extreme, but a similar process is also demonstrated in an Indian federation in which the centre dominated the constituent States - parallels that are striking in light of their vastly dissimilar contexts. The thesis also contributes to the broader study of state formation through what is derived concerning the value of macro historical studies in the comparative, what constitutes success in state-building, and importance of inertia as a factor. By focusing on state institutions rather than individual state-builders, this study depersonalises to a degree the issue of causality in the historiography of state formation in both cases.