Ulster-Scots is a contemporary case of ethnicity-building, materialising in Northern Ireland at the end of the 20th century. As the ‘Troubles’ began to be reinterpreted as being about cultural identity in the 1980s, avenues were sought through which to find a ‘Protestant-ness’ comparative to the considerably more developed discourse of Irishness. It was at this point that Ulster-Scots emerged. While its initial decades were marked by derision, hostility, and resistance, it has gained considerable ground in recent years. This article outlines the development of Ulster-Scots from its beginnings in the late 1980s to the present. Utilising in-depth interviews with a variety of current and historical actors, I contend that this development entailed three phases. First, grass-roots educationalists operated independently while unionist elites lobbied for official recognition. In a second phase, the official recognition and institutionalisation of Ulster-Scots in the wake of the Good Friday Agreement initiated a process wherein the Ulster-Scots Agency came to be established as the key player in the field. A third phase began in the early 2010s with the Agency establishing a monopoly over the processes of Ulster-Scots peoplehood-making.