Objective To characterize white matter alterations in children with isolated or concurrent developmental coordination disorder and/or attention-deficit/hyperactivity disorder (ADHD) compared with typically-developing controls, and to determine whether group differences on motor and attention tasks could be explained by differences in diffusion tensor imaging (DTI) measures. Study design In a cohort of children (n = 85) with developmental coordination disorder, ADHD, or combined developmental coordination disorder+ADHD, we examined 3 major white matter tracts involved in attention and motor processes. Using DTI, the corpus callosum, superior longitudinal fasciculus, and cingulum were analyzed with respect to measures of white matter integrity. Differences in fractional anisotropy (FA), mean diffusivity, radial diffusivity, and axial diffusivity were analyzed using ANOVA. Motor and attentional functioning was assessed using standardized tests, and correlated to DTI measures. Results FA reductions were noted in the frontal regions of the corpus callosum for children with ADHD ( P  = .039), whereas children with developmental coordination disorder displayed similar reductions in regions of the corpus callosum underlying parietal brain regions ( P  = .040), as well as the left superior longitudinal fasciculus ( P  = .026). White matter integrity was impacted in both frontal and parietal regions for children with comorbid developmental coordination disorder+ADHD ( P  = .029; .046). FA was positively correlated with scores on both motor and attentional assessments in a region-specific manner. Conclusion Our findings suggest that alterations in the corpus callosum underlie difficulties in motor and attention functioning. These changes are functionally and regionally distinct and could reflect a neurobiological basis for motor and attention disorders in children.