The purpose of this study was to investigate the impact of three different ankle foot orthoses (AFO) configurations on the function and kinematics of stair locomotion in children with spastic hemiplegia. Nineteen children were evaluated barefoot and with a hinged, posterior leaf spring (PLS) and solid AFO during stair ascent and descent. Stair specific items from the Pediatric Evaluation of Disability Inventory (PEDI) were used to evaluate function, while a motion measurement system was used to evaluate kinematics. The PEDI revealed no significant differences between AFOs and barefoot, although a greater percentage of children were able to keep up with their peers while wearing a hinged AFO. At the ankle, the hinged AFO provided the greatest amount of dorsiflexion during stance. All AFOs reduced plantarflexion in comparison to barefoot. The results of this study indicate that for children with spastic hemiplegia the use of an AFO did not impair stair ambulation.