In recent years the metaphor of knowledge barriers in organisational learning has gained currency to help analyse and explain innovation with complex information technology (IT) in organisations. Despite ongoing research, it is argued that the central concept of a ‘knowledge barrier’ remains under-conceptualised. It is important to address this gap to further our understanding of IT innovation processes in organisations. This paper proposes a framework that clarifies the concept of a knowledge barrier, and integrates two research approaches to explain sources of knowledge barriers. Support for the model is provided using a case study of complex technology innovation in the Australian healthcare sector.