SUMMARY
The aim of this research is to study motivations that drive knowledge sharing in free software communities as explained by Social Exchange Theory. A survey method was adopted in which a questionnaire was administrated during a free software event, answered by members of free software communities. Structural Equation Modelling was used in the data analysis. From a social exchange view, trust, feedback, altruism, status, self-efficacy and reciprocity motivate knowledge sharing in free software communities and some have an indirect influence on knowledge collection and knowledge donation processes. Altruism is the only motivation that directly influences knowledge sharing. Reciprocity is directly linked to knowledge collection and self-efficacy and status are directly linked to knowledge donation. Status is directly and negatively related to knowledge donation. Influence of knowledge collection on knowledge donation was supported. The main contribution is showing the existence of relationships between motivations driving knowledge sharing in free software communities as explained by Social Exchange Theory, instead of investigating a direct relationship between each motivation and knowledge sharing. The findings of this research are useful for leaders of communities who can use them to leverage knowledge sharing.