Global Health has emerged as a flourishing field of study that advances key ideas and debates in International Relations. Twenty-five years since Caroline Thomas's article ‘On the Health of International Relations and the International Relations of Health’ first appeared in the Review, this Special Issue presents a richly diverse collection of articles that are deeply informed by, and offer new insights into, International Relations. The specific focus of this Special Issue is thus decidedly on the rapidly growing field of Global Health research emerging within the discipline of International Relations (IR). It showcases how the study of Global Health is increasingly generating new perspectives on some of the core assumptions and debates in the discipline. Indeed, as the articles in this Special Issue show, the field of Global Health in International Relations is rapidly maturing by drawing upon and challenging a broad range of influences from within IR. At the same time, the articles included herein also contribute to the strong interdisciplinary character that has become such a defining hallmark of Global Health research, which has engaged with scholarship emanating from disciplines like History, Geography, Anthropology, and Sociology, as well as Public Health.