This Companion presents a comprehensive analysis of the World Health Organization’s (WHO) practices and structures, reflecting on its development as a specialised UN agency since its creation. It examines the WHO’s capacity to provide the coordination and leadership needed to address today’s global health challenges. Providing valuable contributions from leading scholars, this timely Companion explores the role of the WHO in today’s global health landscape. It offers a range of insights into the law and practice of the WHO, discussing opportunities for further development including the revision of the International Health Regulations and the ongoing negotiations for the proposed Pandemic Treaty. Drawing on a variety of different legal fields, including biodiversity law, human rights law, and international institutional law, the Companion analyses an ever-growing number of outside influences on the structure and purpose of the organisation. The Elgar Companion to the Law and Practice of the World Health Organization is a vital read for scholars and students of global health law, public international law, international relations, and public health. It is also beneficial for practitioners and policymakers interested in international health regulations.