This research explores the development and circulation of Guild Socialism during the early 20th century following its initial emergence in Edwardian Britain and its rising popularity internationally during the interwar period. In particular, Austria, Germany, Japan, New Zealand, South Africa, and the United States all became vital locations connected to the rise of Guild Socialism. These locations helped to shape the meaning of this subject via the circulation of different forms of practical and theoretical knowledge contributed by an array of middle-class and working-class men and women. Including craftsmanship, translation, national history, industrial democracy, and different conceptions of political economy linked to corporatism, Marxism, and syndicalism, which contributed to the development of Guild Socialism. This study breaks new ground by assessing this ‘ism’ with the categories of knowledge and knowledge systems that help to highlight the diversity of meanings attached to Guild Socialism and the array of men and women from working-class and middle-class backgrounds who were involved in its production through their involvement with the National Guilds League (1915-23). Moreover, they help to reveal the global dimensions of Guild Socialism and the linkage forged by knowledge between guild socialists around the world, while also highlighting how this subject was reflective of the changes in the wider composition of the British Left during this period.