This chapter discusses sex differences that are found in a variety of tests of visuospatial abilities ranging from standardized paper-and-pencil or computerized tasks to tests of way-finding ability and geographical knowledge. Visuospatial information processing involves interplay of multiple cognitive processes, including visual and spatial sensation and perception, a limited capacity visuospatial working memory, and longer-term memories where visual and spatial information may be encoded in many ways. Certain visuospatial and mathematical abilities are related, and visuospatial sex differences have been suggested to contribute to observed sex differences in mathematics performance. Many cultures show similar patterns of visuospatial sex differences, a finding that seems to support theories based on the principles of evolutionary psychology. The chapter explores how factors rooted in biology, specifically the what-where visual systems, hemispheric lateralization, and exposure to sex steroid hormones, may relate to visuospatial skill and to sex differences in those abilities.