Animal cognition is the study of cognitive processes such as learning and memory in a variety of species. While the cognition of mammals and birds has been researched intensely, not much is known about reptile cognition. However, because of the evolutionary connection between the orders a sound knowledge of reptile cognition is needed to fully understand the evolution of cognition. It was the aim of the present thesis to contribute to the better understanding of reptile spatial cognition. After an overview on cognition research and reptile spatial navigation provided by the first two chapters, chapter 3 and 4 describe studies on eight-arm radial maze behaviour in the red-footed tortoise (Geochelone carbonaria) and the jewelled lizard (Lacerta lepida), respectively. Both the tortoises and the lizard showed a strong preference for using response stereotypic behaviour when navigating the maze. Thus, compared to mammalian navigation mechanisms, reptile spatial behaviour might rely more strongly on intrinsic cues. Chapter 5 describes a study showing that red-footed tortoises were able to master a spatial detour task after observing a conspecific demonstrator while they were unable to manage it by themselves. Given the solitary nature of this species the ability to learn socially suggests access to a large problem-solving repertoire. The study described in chapter 6 examined the ability of red-footed tortoises to perceive and comprehend 2D images. The findings showed that they were able to distinguish food and non-food items when presented with 2D photographs. Chapter 7 presents findings showing the ability of red-footed tortoises to use a touchscreen, a skill hitherto undemonstrated in reptiles. Furthermore, the tortoises were able to transfer knowledge acquired in the touchscreen set-up to a ‘real-world’ 3D arena. In the final General Discussion I have summarized the most important data of my five empirical studies and conclude with the question of what this tells us about reptilian cognition. The limited amount of data suggest that cognitive processing of mammals, birds, and reptiles are quite similar. However, to enable direct comparisons of the different orders and to achieve a conclusive level of evidence, much more basic research is needed.