BACKGROUND:Motor development research has seen substantial recent growth. However, much remains to be understood about the nature and extent of motor impairments in neurodevelopmental disorders, including their potential as early markers and/or causal determinants of downstream functioning in other domains. AIMS AND METHODS:In this narrative review, drawing primarily on the autism literature by way of example, we review current accounts of the nature and consequences of motor functioning. We consider conventional approaches to measurement and study design, and current limited approaches to tackling heterogeneity. CONCLUSIONS AND IMPLICATIONS:We argue that ongoing adherence to traditional diagnostic outcome classification stands in the face of mounting evidence that characteristics of neurodevelopmental disorders lie on a continuum with variability in the general population, and that three broad research avenues stand to offer a better understanding of motor functioning: The use of technology and advanced statistical methods for a more nuanced understanding of motor abilities; exploiting the prospective longitudinal tracking of at-risk infants to understand developmental consequences of early motor difference; and employing randomized controlled trials to test the utility of motor therapies whilst also testing causal hypotheses about the role of motor functioning.