Abstract: A walking splint for substantially immobilizing the ankle joint of a human includes four discrete members that are adapted for placement on the posterior, lateral, medial and anterior portions of the lower leg and foot to substantially encase the ankle joint. The members conform closely to the anatomical features of the lower leg and foot and include an inner layer of compressible foam material to enable a snug fit over a range of sizes of leg and foot. The members are held in place by a plurality of spaced, adjustable straps that encircle the members. The posterior member of the splint extends to underlie the foot and holds the foot in a constant right angular relation to the leg. The portion of the posterior member underlying the foot includes an integrally formed arch support and, preferably, the exterior surface of the underlying portion comprises an antiskid surface.