The research includes various constructs based on social exchange theory and social cognitive theory. This study mainly explored the relationships among organisational justice, trust, commitment and knowledge-sharing cognition and verified their mediating effects through two variables of trust and commitment. A survey utilising a questionnaire was used with 252 IT professionals from IT companies and departments in Taiwan. Structural equation modelling was used to analyse the data and to evaluate the research model. The results showed that the research model fitted the data well, and the main determinant of knowledge-sharing intention was the building of organisational justice between knowledge intensive workers, confirming our hypotheses that trust and commitment foster organisational commitment. In turn, organisational commitment will help to build individual knowledge-sharing self-efficacy and both directly and indirectly affect intentions to share knowledge. (Contains 6 tables and 2 figures.)