Objective: To synthesize the available evidence on the effects of constraint-induced movement therapy (CIMT) in children with hemiplegic cerebral palsy (CP), focusing on upper limb functional outcomes and neuroplasticity-related changes assessed through direct or indirect measures. Methods: This scoping review was conducted in accordance with PRISMA-ScR guidelines and was prospectively registered on the Open Science Framework (DOI: 10.17605/OSF.IO/DU8RE). A search of four databases (PubMed, Scopus, Embase, and Web of Science) was performed to identify studies involving children (0–18 years) with CP who received CIMT as the primary intervention. Eligible studies assessed neuroplasticity through neuroimaging or neurophysiological techniques. Results: Eleven studies involving 221 children met the inclusion criteria. CIMT protocols varied in duration, intensity, and setting (e.g., clinical, home-based, camp-based). Across studies, CIMT was associated with improvements in upper limb function and spontaneous use. Neuroplastic changes included increased activation in the contralateral sensorimotor cortex, normalization of somatosensory responses, and structural brain adaptations. Adjunctive therapies such as repetitive transcranial magnetic stimulation, transcutaneous auricular vagus nerve stimulation, or occupational therapy further enhanced outcomes. Conclusion CIMT is an effective intervention that promotes cortical reorganization and improves motor function in children with hemiplegic CP. Customizing rehabilitation based on neurophysiological profiles may optimize clinical outcomes.