Objectives: The aim of this study was to investigate the short-term effects of spinal manipulation (SM) on wrist muscle spasticity and manual dexterity in participants with cerebral palsy (CP).Methods: After baseline examination, 78 participants with spastic CP (7-18 years) without contractures or hyperkinetic syndrome were randomly allocated into 2 groups. The experimental group underwent SM to the cervical, thoracic, and lumbar spine, and the control group received sham SM. A second evaluation was performed 5 minutes postintervention. Wrist muscle spasticity was measured quantitatively with NeuroFlexor (Aggero MedTech AB, Solna, Sweden), a device assessing resistance to passive movements of different velocities. Between-group difference was calculated using the Mann-Whitney U test. Manual dexterity was evaluated by the Box and Block test.Results: In the experimental group, muscle spasticity was reduced by 2.18 newton from median 5.53 with interquartile range 8.66 to median 3.35 newton with interquartile range 7.19; the difference was statistically significant (P = .002). In the control group, reduction in spasticity was negligible. The between-group difference in change of muscle spasticity was statistically significant (P = .034). Improvement of manual dexterity was not statistically significant (P = .28).Conclusions: These findings suggest that SM may, in the short term, help to reduce spasticity in participants with CP. Long-term effects of SM on muscle spasticity have yet to be studied.