This paper examines the problems that may arise, particularly for military personnel, when the requirements of doing one's duty seem to come into conflict with the demands of loyalty. This conflict is especially problematic because loyalty is often seen, especially by serving military personnel, as the highest of military virtues. The paper introduces a categorisation of ethical issues into two main types, which are referred to as ‘ethical dilemmas’ and ‘tests of integrity’ which is then used to clarify the issues (...) involved when duty and loyalty come into conflict. It is argued that a true understanding of loyalty and disloyalty means that the demands of loyalty can never legitimately override a genuine duty to follow orders. (shrink)