Introduction . Mangement of hypertonia in dyskinetic cerebral palsy is challenging. The present study was designed to compare the efficacy and safety of gabapentin as add-on therapy to trihexyphenidyl in the treatment of children with dyskinetic CP. Methods . An open labelled, randomized controlled trial was conducted among 60 children aged 3–9 years with dyskinetic CP (GMFCS 4-5). The participants were randomized into two groups: Gabapentin group receiving gabapentin with trihexyphenidyl (n = 30) and Trihexyphenidyl group receiving trihexyphenidyl alone (n = 30). Primary outcome measures include total Dyskinesia Impairment Scale (DIS), Dystonia Severity Assessment Plan (DSAP) and International Classification of Functioning Disability, and Health-Children and Youth Version (ICF-CY) assessed at four weeks and twelve weeks. Secondary outcome measure include frequency and nature of adverse drug reaction observed after initiation of drug therapy. Results . Out of 60 children, five children in gabapentin group and two children in trihexyphenidyl group were lost to follow up at twelve weeks. There was significant reduction in severity of dystonia in both the groups at four weeks as well as at twelve weeks (DIS: P < 0.001, DSAP: P = 0.007, ICF-CY: P < 0.001) but when the data were compared between the groups, there was no significant reduction in severity of dystonia at four weeks and at twelve weeks (DIS: P = 0.09, DSAP: P = 0.49, ICF-CY: P = 0.25). Constipation (11.5% in gabapentin group and 14.3% in trihexyphenidyl group) was the commonest side effect observed in both groups and both gabapentin as well as trihexyphenidyl were well tolerated without any serious side effect. Conclusion . Trihexyphenidyl alone is as effective as combination of gabapentin with trihexyphenidyl in reducing the severity of dystonia at twelve weeks. Hence, there is no added benefit of gabapentin in management of dystonia in children with dyskinetic CP.