Background. Advancing the science of knowledge translation (KT) in occupational therapy is critical. Explicit application of theory can advance this science; yet, how theory is applied and the degree to which it can guide research remain poorly defined.Purpose. To understand how theory is applied within KT research.Methods. A scoping review was conducted to examine and summarize the extent, range, and nature of the application of three specific KT theories: Diffusion of Innovations, Promoting Action on Research Implementation in Health Services framework, and Theory of Planned Behaviour.Findings. Theory use was seen most frequently in medicine and nursing. Only 3 of 90 articles were in rehabilitation. Five approaches to theory application were found, the most common being the use of to predict success of KT (57/90).Implications. In-depth study of the importance and methods of theory application in KT research is needed, in particular in occupational therapy.