The purpose of this study was to examine the effects of concussion on gait stability when either a cognitive or motor perturbation is imposed. Fourteen individuals suffering from a grade II concussion and 14 matched controls performed a single task of level walking, a continuous sequential question and answer task while walking, and an obstacle-crossing task. Common gait spatial/temporal measurements, whole-body center of mass motion, and center of pressure trajectory were assessed. Concussed individuals adopted a more conservative strategy to maintain gait stability. Some measurements indicating conservative gait were seen during obstacle crossing, but this was most evident during the Q&A task. Concussed individuals also displayed signs of possible instability during the Q&A task. The question and answer task was most sensitive to distinguishing concussed individuals from healthy individuals, supporting the use of a similar dual-task modality in future testing after concussion to determine a proper time for return to activity.