Background: Mirror movements (MM) in pediatric stroke patients are related to abnormal ipsilateral Corticospinal Tract (CST). Whilst children with contralateral CST wiring may also present with MM, the role of interhemispheric interactions remains unknown. Here, we investigated the role of interhemispheric inhibition, facilitation and functional connectivity on MM in children with contralateral CST after arterial ischemic stroke. Patients and Methods: 16 patients with pediatric stroke and contralateral CST wiring were included. Participants underwent multimodal examination including dual-pulse transcranial magnetic stimulation to measure interhemispheric inhibition (10 milliseconds interstimulus interval, measured on the flexor digitorum superficialis) and resting-state functional MRI to assess motor network functional connectivity between primary motor cortices. MM were measured with the Woods and Teuber scale in each hand (hand opening and closing, finger opposition and sequential finger movement). We conducted non-parametric correlation analysis and interpreted r-values as absent (<0.25), fair (0.25– 0.50), moderate (0.50– 0.75) or excellent (>0.75). Results: Higher MM-scores in the affected hand were related to (1) lower interhemispheric functional connectivity between the primary motor cortices (r = −0.48, p = 0.06), (2) higher inhibition from the non-lesioned to the lesioned hemisphere (r = 0.65, p = 0.01) and (3) slightly higher facilitation from the lesioned to the non-lesioned hemisphere (r = 0.36, p = 0.27). MM-scores in the non-affected hand were higher with facilitation from the lesioned to the non-lesioned hemisphere (r = 0.76, p = 0.006). Conclusion: In children with arterial ischemic stroke and contralateral CST wiring, the active motor cortex may facilitate the contralateral motor cortex and increase the occurrence of MM, highlighting the importance of interhemispheric interactions for this phenomenon.