Gait impairments affect children with brain abnormalities across the severity spectrum, from mild (developmental coordination disorder-DCD) to more severe (cerebral palsy-CP). In CP, decreased selective motor control (SMC) during gait results in simplistic, or more synergistic, movement patterns. Such patterns are also seen in typically developing (TD) toddlers, but where normally the gait pattern matures, in children with CP, the primitive control patterns persist. In CP, decreased SMC during gait is associated with poorer conventional treatment outcome. Hence, level of SMC during gait may predict intervention outcomes in CP. To date, there are no studies analysing SMC in DCD. We hypothesise that in DCD, similar immature synergistic patterns prevent the development of typical movement. However, in DCD, we expect abnormalities in SMC only when children combine walking with another task. By comparing SMC during gait in DCD, CP, and TD children with and without dual tasks, we can gain a fundamental understanding of the mechanisms of impaired SMC in different disorders. This will help the development of individualised interventions that target SMC to improve gait in these populations.