Cerebral Palsy (CP) is a neurological disorder caused by non-progressive brain malformation during fetal or infant development, leading to movement impairments, muscle weakness, and spasticity. Spastic CP is the most prevalent type, affecting nearly 75% of individuals with CP. Spasticity, characterized by increased muscle stiffness and resistance to passive stretching, often results in joint deformities, contractures, and restricted mobility, significantly affecting the quality of life. Managing spasticity remains a challenge for rehabilitation teams, requiring effective interventions to improve functional independence. Instrument-Assisted Soft Tissue Mobilization (IASTM) has gained attention as a non-invasive technique to enhance flexibility and reduce spasticity. It involves using specially designed tools to break down myofascial adhesions, stimulate fibroblast activity, and promote collagen remodeling, improving muscle function. While IASTM has shown promise in musculoskeletal conditions, research on its effects in CP remains limited, particularly regarding its immediate impact on spastic muscles. This study aims to evaluate the immediate effects of IASTM on hamstring and gastrocnemius flexibility and spasticity in individuals with spastic CP. The primary objective is to assess dynamic muscle length (R2-R1) before and after IASTM treatment using the Modified Tardieu Scale (MTS) and compare pre- and post-treatment values to determine its immediate effectiveness. This experimental pre-post study will be conducted at a tertiary healthcare center, involving individuals with spastic CP aged four years and above. Participants must have a Modified Ashworth Scale (MAS) grading of 1+ to 3 for the hamstring and gastrocnemius following routine anti-spastic medications. Exclusion criteria include severe contractures, recent botulinum toxin injections, lower limb surgeries, uncontrolled epilepsy, or skin infections over the treatment area. Ethical approval from the Institutional Ethics Committee (IEC) and Departmental Review Board (DRB) will be obtained before recruitment. Parents or guardians will receive detailed information about the study, and written informed consent will be collected. Pre-treatment assessment will include MAS grading for spasticity, MTS measurements for dynamic muscle length (R2-R1), and passive range of motion (PROM) measurements for knee flexion and ankle dorsiflexion using a goniometer. The IASTM treatment will be administered using a stainless-steel Graston tool, with slow, prolonged strokes applied along the muscle fibers from origin to insertion at a 30-60 degree angle for 2-3 minutes per muscle. Immediately post-treatment, reassessment of MAS grading, MTS measurements for dynamic muscle length, and goniometric PROM values will be conducted. Ice packs wrapped in a towel will be applied to the treatment area for 5-7 minutes to minimize potential soreness. The collected data will be analyzed to determine the effectiveness of IASTM in reducing spasticity and improving muscle flexibility. Given the limitations of current treatment methods, IASTM has the potential to serve as a non-invasive, cost-efficient approach to managing spasticity in CP. If proven beneficial, it could be integrated into rehabilitation programs, improving functional outcomes and mobility in individuals with CP.