This chapter reviews research on spatial abilities, which is concerned with individual differences in how people mentally represent and manipulate spatial information to perform cognitive tasks. We first review factor analytic studies of spatial abilities. This research tradition provided strong evidence that spatial ability is differentiated from general intelligence and that it is not a single, undifferentiated construct, but instead is composed of several somewhat separate abilities. We next review analyses of performance on spatial abilities tests by cognitive psychologists, which has shown that different spatial abilities may depend more or less on speed of processing, strategies, quality of spatial images, active maintenance of spatial information, and central executive processes. Third, we examine individual differences in large-scale or environmental spatial abilities such as wayfinding and navigation. Research on this topic has begun to characterize the factor structure of large-scale spatial abilities and these abilities’ relation to more traditional measures of spatial abilities. Finally, we consider some of the functions of spatial ability in occupational and academic performance, including surgery, mechanical reasoning, and mathematical problem solving.