The onset of locomotion heralds one of the major life transitions in early development and involves a pervasive set of changes in perception, spatial cognition, and social and emotional development. Through a synthesis of published and hitherto unpublished findings, gathered from a number of converging research designs and methods, this article provides a comprehensive review and reanalysis of the consequences of self-produced locomotor experience. Specifically, we focus on the role of locomotor experience in changes in social and emotional development, referential gestural communication, wariness of heights, the perception of self-motion, distance perception, spatial search, and spatial coding strategies. Our analysis reveals new insights into the specific processes by which locomotor experience brings about psychological changes. We elaborate these processes and provide new predictions about previously unsuspected links between locomotor experience and psychological function. The research we describe is relevant to our broad understanding of the developmental process, particularly as it pertains to developmental transitions. Although acknowledging the role of genetically mediated developmental changes, our viewpoint is a transactional one in which a single acquisition, in this case the onset of locomotion, sets in motion a family of experiences and processes that in turn mobilize both broad-based and context-specific psychological reorganizations. We conclude that, in infancy, the onset of locomotor experience brings about widespread consequences, and after infancy, can be responsible for an enduring role in development by maintaining and updating existing skills.