In 1921, the United States introduced national immigration quotas. Although designed to curb the arrival of ‘undesirables’ from south-east Europe, this quota system also applied to Britain and its white Dominions. By 1929, Australia, New Zealand, and South Africa were each allocated 100 quota places per annum. The British quota was far greater, but still struggled to meet demand. Through a focus on the Australian example, this article investigates how an immigration regime intended to bolster America’s ‘Anglo-Saxon’ identity also exposed the limits of Anglospheric kinship by closing the gates to white Britons. Although the quotas had a comparatively minor impact on Britons, their exclusion held great significance in the context of Anglo-American relations, where the rhetoric of transnational white solidarity produced expectations of unqualified welcome in the United States. After 1921, as such welcome disappeared and then failed to rematerialize, the global community of white men’s countries was shaken and remade.