Analysis of gaze data collected during experiments is an essential part of any study that deals with eye tracking. In turn, analysis of gaze data is not a trivial procedure, on account of the nature of eye movement, peculiarities of human vision, and the imperfection of the measurement tools. In this chapter, we first draw out the most common issues that researchers are trying to resolve for analysis of gaze data, then present in detail the well-known methods and procedures of gaze data analysis, and finally point to the latest achievements in this field. The chapter contains a specification of the most promising directions in this field of research. We finish with a brief description of the most well-known academic and commercial tools that have been developed for gaze data visualisation and analysis. This chapter is based on an updated version of work originally published by Špakov in 2008.