The purpose of this thesis has been to illustrate the conditions for development of judgement-based professional skill, by means of institutionalised officer training. The study has been based on two questions: 1) What is, in the context of the exercise of the officer profession and the military school environment, the nature and epistemological foundations of the judicious action? 2) In what way can institutionalised officer training ensure the development of the judgment of future military leaders?This study is presented in the form of a scientific essay, departing from a personally experienced dilemma, which subsequently gets subjected to personal reflection as well as theoretical analysis, in which the author acts as both the subject and the object. The explo-ration has its starting point in the assumption that there is a decisive difference between knowing-that, knowing-how and knowing what, of which especially the latter requires judge-ment. Through a survey of the epistemological concepts of Aristotle and of Maria Hammarén applied to the professional skill of the officer and the military school environment, it is estab-lished that the judicious action is an indispensable part of the professional skill and that per-sonal judgement in its turn is a trained ability, first of all shown in action. A conclusion in this respect is that an officer needs the ability to make judicious decisions based on intuition as well as on analytical thinking, depending on the situation. The author puts Hammarén’s ideas of professional skill being developed through a combination of experience and reflection preferably organised in a reflecting practice, in the context of the military teacher.Another conclusion is that the judgement in (not least the military) professional skill in fact is the sound judgement, i.e. the ability to make and implement ethically well-founded decisions. This subject is further explored in relation partly to Hannah Arendt’s ideas of the role of sound judgement in a bureaucratic organisation, and partly to moral philosophical theories, put in the context of military professional skill and school environment. A conclu-sion is that the ethical education must aim at developing the willingness to do good, as well as the eye for judging what actions being morally right in a certain situation.The author also presents possible methods for establishing a reflective praxis within a military school environment.