AimTo study if functional electrical stimulation (FES) of the peroneal nerve, which activates dorsiflexion, can improve body functions, activities, and participation and could be an effective alternative treatment in individuals with unilateral spastic cerebral palsy (CP).MethodA randomized cross‐over trial was performed in 25 children with unilateral spastic CP (classified in Gross Motor Function Classification System levels I and II) aged 4 to 18 years (median age at inclusion 9 years 8 months, interquartile range = 7 years–13 years 8 months), 15 patients were male. The study consisted of two 12‐week blocks of treatment, that is, conventional treatment (ankle foot orthosis [AFO] or adapted shoes) and FES, separated by a 6‐week washout period. Outcome measures included the Goal Attainment Scale (GAS), the Cerebral Palsy Quality of Life questionnaire, and a three‐dimensional gait analysis.ResultsEighteen patients completed the trial. The proportion of GAS goals achieved was not significantly higher in the FES versus the conventional treatment phase (goal 1 p = 0.065; goal 2 p = 1.00). When walking while stimulated with FES, ankle dorsiflexion during mid‐swing decreased over time (p = 0.006, average decrease of 4.8° with FES), with a preserved increased ankle range of motion compared to conventional treatment (p < 0.001, mean range of motion with FES +10.1° compared to AFO). No changes were found in the standard physical examination or regarding satisfaction with orthoses and feelings about the ability to dress yourself. In four patients, FES therapy failed; in 12 patients FES therapy continued after the trial.InterpretationFES is not significantly worse than AFO; however, patient selection is critical, and a testing period and thorough follow‐up are needed.