Abstract: Eye tracking refers to the process of tracking the movement of the eye and determining where the user is looking. The aim of this paper is to present a review on various techniques used for eye tracking. There are a number of principles used in measuring eye movements, including measurements of electric and photoelectric signals, tracking a number of visual features in the image of the eye, measuring relative reflection of infra-red (IR) light, and using either mechanical or optical levers or a magnetic field. This paper also includes the factors involved in the selection of a particular eye tracking method. Finally, it includes a light on some of the applications of the eye tracking technique.