This article examines the relationship between Hinduism and war and the extent to which the fundamental concepts of humanitarian law are recognized in Hinduism. After reviewing the sources of Hinduism, it considers the permissibility and types of war in ancient India, explores the rules of warfare and investigates whether war was a matter of course or regarded as a ruler’s last choice. It then sets out the humanitarian principles that already applied at that time. Finally, it considers how far the concepts of Hinduism have helped in the development of international humanitarian law.