Feminist approaches to international law have been mischaracterised by the mainstream of the discipline as being a niche field that pertains only to women’s lived experiences and their participation in decision-making processes. Exemplifying how feminist approaches can be used to analyse all areas of international law, this book applies posthuman feminist theory to examine the regulation of new and emerging military technologies, international environmental law and the conceptualisation of the sovereign state and other modes of legal personality in international law. Noting that most posthuman scholarship to date is primarily theoretical, this book also contributes to the field of posthumanism through its application of posthuman feminism to international law, working to bridge the theory and practice divide by using posthuman feminism to design and call for legal change. This interdisciplinary book draws on an array of fields, including philosophy, queer and feminist theories, postcolonial and critical race theories, computer science, critical disability studies, science and technology studies, marine biology, cultural and media studies, Indigenous onto-epistemologies, critical legal theory, political science and beyond to provide a holistic analysis of international law and its inclusions and exclusions. This interdisciplinary book will appeal to students and scholars with interests in legal, feminist and posthuman theory, as well as those concerned with the contemporary challenges faced by international law.