This thesis describes how to visualize a driver's eye movements and gaze direction in a simulator. The thesis also describes how to implement such a system and what problems to expect. In the implemented system, Gaze Tracker, the visualization and detection is made in real-time and Smart Eye Pro was the system used to detect eye movements and eye position. Gaze Tracker works as an add-on application to the driving simulator of VTI, Simulator III, and this was also the simulator used in the final tests. These tests were considered to be successful and the visualization was considered to fulfill the goal of this thesis. This thesis also describes how a human uses his/her eyes and what kind of techniques possible to use for detection of these eye movements. Techniques mentioned in this thesis are contact lenses, electrooculography (EOG) and videooculography (VOG). Because of the close usage of the driving simulator of VTI this thesis also gives a description of their latest simulator and what kind of simulations it can be used for.