OBJECTIVE: To assess the effectiveness of the resting foot splint to prevent ankle contracture. METHODS: We performed a randomized controlled trial in 33 patients with brain injury with ankle dorsiflexor weakness (muscle power ≤grade 2). Both groups continued conventional customized physical therapy, but the patients in the foot splint group were advised to wear a resting foot splint for more than 12 hours per day for 3 weeks. The data were assessed before and 3 weeks after the study. The primary outcome was the change in ankle dorsiflexion angle after 3 weeks. RESULTS: Before the study, there were no differences between groups in gender, age, time post-injury, brain injury type, initial edema, spasticity, passive range of ankle dorsiflexion, Fugl-Meyer score (FMS), or Functional Ambulation Classification. A significant improvement in ankle dorsiflexion angle, and FMS was found after 3 weeks in both groups. The splint group showed more spasticity than the control group after 3 weeks (p=0.04). The change of ankle dorsiflexion angle, foot circumference, spasticity, and FMS after adjusting initial value and spasticity were not significantly different between the 2 groups. CONCLUSION: Wearing a resting foot splint for 3 weeks did not affect joint mobility in patients with subacute brain injury regularly attending personalized rehabilitation programs. Further studies of larger sample sizes with well controlled in spasticity are required to evaluate the effects of the resting foot splint.