Actors responding to humanitarian crises employ numerous principles to guide their actions and decisions. Among these, four have come to represent the core principles of humanitarian action: humanity, impartiality, neutrality and independence. These four enjoy a complex relationship, forming an integral set that can be both mutually reinforcing and in tension with one another. These principles hold a theoretical value, defining key distinctions between humanitarians and other actors, as well as a pragmatic value in guiding operational decision-making. Much debated, there is broad accord as to their definition (with the exception of neutrality), but little definition of what they look like in practice. Research has shown that consistent adherence to these principles can improve the access and security of an organization, and also shows that humanitarians must frequently compromise principles if they are to overcome operational challenges.