A hierarchical model of organisational commitment of sport volunteers has been presented in the article. It is based on the three-component model of organisational commitment by Allen and Mayer and Kohlberg's model of moral development. The comparative analysis of these models has revealed differences between them. The developed model includes the levels of primitive, continuous, external, normative and emotional commitment; and Kohlberg's model includes the following stages: Obedience and Punishment Orientation, Individualism and Exchange, Good Interpersonal Relationships, Maintaining the Social Order, Social Contract and Individual Rights, and Universal Principles. The efficiency of different levels has been presented. Some recommendations for volunteer managers on maintaining the experienced volunteers and attracting new ones to the organisation, depending on the organisational commitment level of a volunteer, have been given. Also, the model includes external liabilities as social environment and culture can affect an individual and make him/her begin or continue volunteer activities. It is assumed that the activities of the volunteers with strong emotional commitment can be the most efficient in the activities of sport organisations, because they are strongly committed to the organisational success and are willing to devote themselves fully to the success of the organisations where they are working. Besides, the model also suggests that the development of volunteers' commitment may not have the sequential nature of the each level change. The overall goal of managing volunteers is not only making sport volunteers morally committed, but also make them want to work for the same sport organisation. The developed model should be approbated taking into account peculiarities and features of a sport organisation as well as different kinds of sports. The use of the model can act like a diagnostic tool which helps sport managers motivate volunteers according to the state of their organisational commitment.