To investigate the effects induced by wearing an orthosis during the rehabilitation process, 23 ankle sprain patients (degrees I and II) were evaluated in three conditions (reference, with an elastic compression stocking and with an orthosis), 14 h, 10 and 30 days on average after their injury and compared with those of 30 age-matched healthy individuals. The patients were tested with separate measurements of the reaction forces under each limb to highlight the possible compensatory mechanisms between the sound and the injured legs. Their postural stability was enhanced during unilateral orthosis wear, explained by a bilateral effect involving both feet. Wearing a compression stocking induced comparably mild intermediate effects compared with the effects observed with the orthosis. These effects were constant throughout the next month. Following lateral ankle sprain, wearing an orthosis allows patients to improve postural function a few hours after the injury to 1 month later. Only cutaneous pressure intervening without mechanical maintenance induced mild effects, indicating that orthosis effects on postural control could partly result from its sensorial stimulation. It, therefore, seems relevant to prescribe orthosis wear for at least 1 month.