Lace-up ankle braces reduce the incidence of ankle sprains and have been hypothesized to do so through both mechanical and neuromuscular mechanisms.To determine the effect of lace-up ankle braces on surface electromyography (sEMG) measures during walking in adults with chronic ankle instability (CAI).Randomized crossover.Laboratory.Fifteen adults with CAI.Surface EMG activity was recorded from the anterior tibialis, peroneus longus, lateral gastrocnemius, rectus femoris, biceps femoris and gluteus medius during treadmill walking with and without lace-up ankle braces. The dependent variables were sEMG amplitude 100 ms pre- and 200 ms post-initial contact, time of activation relative to initial contact, and percent of activation across the stride cycle.When compared to no brace, ankle bracing resulted in lower pre-contact amplitude of the peroneus longus (p = 0.02). The anterior tibialis, peroneus longus, rectus femoris, and gluteus medius were activated later relative to initial contact (p < 0.03). The peroneus longus and rectus femoris were activated for a shorter percentage of the stride cycle (p < 0.05).Braces cause a change in neuromuscular activity during walking. Clinicians should be aware of these changes when prescribing braces, as it may relate to the mechanism in which braces decrease sprains.