Purpose: Cerebral palsy (CP) is a common pediatric motor disability characterized by motor impairments and spasticity. This study assesses the feasibility of employing near-infrared spectroscopy (NIRS) to objectively evaluate muscle spasticity in children with CP undergoing botulinum toxin type A (BoNT-A) treatment. Methods: Three participants aged 5–16 years with spastic lower limbs were monitored for changes in the tissue oxygenation index (TOI%) and spasticity levels using the Modified Ashworth Scale (MAS) over 6 months. NIRS measurements were collected at baseline and several intervals following BoNT-A administration. Results: Transient increases in TOI% were observed during the first 2–4 weeks post-injection, coinciding with reductions in spasticity. However, by 6 months, TOI% values experienced a moderate decline. Conclusions: This descriptive analysis highlights the potential of NIRS as a non-invasive tool for real-time monitoring of muscle spasticity treatment efficacy. Further studies with larger sample sizes are needed to validate these findings and establish NIRS as a complement to existing clinical tools for muscle spasticity evaluation and management.