This thesis breaks new ground by examining the Irish population in South Africa during the twentieth century. While the Irish diaspora continues to captivate the minds of scholars around the world, South Africa has generally occupied a marginal position within this much larger discourse. As a result, the historiography that has developed around the Irish in South Africa is quite modest and overwhelmingly focused upon the nineteenth century. Even for the handful of existing works that do venture into the twentieth century, analysis tends to end either before the Great War or immediately after the Irish Revolution. What is wrapped up in this is the assumption that the Irish in South Africa ceased to be a coherent group after the initial decades of the twentieth century. Historians of South Africa have also tended to concur with this thought, assuming that Irish identity was inherently transient in South Africa and that Irish individuals were destined to shed their distinct ethnic awareness within South Africa’s racially charged society. This thesis puts these popular beliefs to the test, by examining the Irish population in South Africa during the rough time period between the Irish Revolution and South Africa’s declaration of a republic. It demonstrates that previous assumptions regarding the Irish experience in South Africa do not hold up to close inspection and argues that far more nuance is required when discussing English-speaking white cohorts in South Africa generally. While the early to mid-twentieth century was a period of immense change in Ireland and South Africa – from which Irish South Africans were not immune – this thesis maintains that the Irish continued to represent a distinct ethnic cohort in South Africa throughout the first half of the twentieth century.