Spatial cognition represents one of the best-established sex differences in cognitive science. There is a pervasive tendency for males to outperform females on multiple spatial reasoning tasks. While prenatal hormones may provide a foundation for these differences, childhood experience also plays an important role. This current article examines how biological factors may interact with environmental and cultural factors. Of particular interest is the cross-cultural literature in which children’s naturalistic experiences exploring their environments can be linked to the development of spatial skills. Based on the examined research, children who gain more navigational experience tend to perform better on spatial tasks. Because boys typically have greater opportunities to explore and navigate, this difference in experience may contribute to the observed sex differences in spatial performance.