A significant proportion of the collective wisdom of any organisation comes from its employees. However, organisations are still struggling with ways to compel their employees to share their best knowledge. The paper introduces the concept of knowledge ownership as a major building block in theorising knowledge sharing in the firm. A distinction is made between organisational ownership which refers to the organisation’s rights to knowledge and individual ownership which refers to the individual’s rights to knowledge. On the basis of this, the paper examines the relationship between employee ownership perceptions and their willingness to share their knowledge assets, both tangible and intangible. In conjunction, the paper also examines the influence of the work environment on fostering employee ownership beliefs. The paper proposes a model to examine the relationship between knowledge sharing and the perceptions of knowledge ownership in the context of codified and tacit knowledge assets.