In knowledge engineering, modelling knowledge is the process of structuring knowledge before implementation. A crucial part of system development depends on the acquiring and structuring, since the quality of system's contents is of decisive importance for making good decisions. Models are needed to assure that all the required knowledge is present. However, the current models tend to be large and this makes it hard to get a grip on the knowledge presented by the model. Also, many models are difficult to use and the users have to be experts on the models before using them. To avoid these problems, we introduce the User-Centred Knowledge Model (t-UCK) for modelling knowledge. The model supports different users, i.e., domain experts, knowledge engineers and end-users, to model, implement, test, consult, and educate through the use of graphic representation and visualisation.