Cerebral palsy (CP) leads to deficits in postural control and adaptive responses to balance perturbations. This study investigated the influence of visual input on electromyographic (EMG) reflex responses to sudden anteroposterior trunk destabilization in young individuals with spastic hemiparesis or diplegia compared to typically developing controls. Twenty-two participants (8 with CP and 14 controls, ages 12–25 years) underwent controlled forward–backward trunk perturbations under two conditions: eyes open (EO) and eyes closed (EC). EMG response amplitude and latency were recorded from six postural muscles and analyzed statistically. Results: In the CP group, removing vision (EC) elicited significantly higher muscle activation amplitudes in distal muscles (tibialis anterior and gastrocnemius) compared to EO (p < 0.05), whereas the control group showed no amplitude changes between conditions. Across both visual conditions, reflex response latencies were markedly prolonged in the CP group relative to controls (e.g. tibialis anterior ~120 ms vs. ~90 ms in controls; ~30% delay, p < 0.05). No significant differences in latency were found between EO and EC within either group. These findings indicate that children with CP rely more on vision to maintain postural stability, exhibiting amplified muscle responses when visual feedback is absent and consistently slower reflex activation than neurotypical peers. Conclusion: Visual input has a greater modulatory effect on postural reflexes in spastic CP, and reflex latency emerges as a sensitive indicator of neuromotor impairment. The study underscores the importance of assessing and training postural responses under varied sensory conditions in rehabilitation for CP.