Crouch gait is the gait abnormality consisting of excessive knee flexion with a crouched posture. This is often found in patients who suffer from the medical condition known as cerebral palsy (CP). This paper proposes a new, purely mechanical device that aims to alleviate this crouch gait in CP patients. A passive knee locking mechanism was attached to a commercial knee brace to support stance stability. The device utilizes only the wearer’s body weight to actuate this knee locking mechanism. Initial studies were then conducted on healthy persons to evaluate the knee kinematics when using the device. The results suggest that this device has the ability to improve stability during the stance phase.