Long-span cable-supportedLong-span bridges bridges areGyroscopic stabilizer sensitive to wind effects due to the deck slenderness, structural properties, and aerodynamic loads. Flutter is usually a major design concern. This study continues the investigation on a prototype of a gyroscopic device, used as an active stabilizer to improve flutter performance. A model of the gyroscopic device, installed at multiple sectional positions under the bridge deck, is used to assess its effectiveness in increasing the critical flutter wind speed. A parametric study is conducted to evaluate the stabilizer’s performance on a benchmark long-span cable-supported bridgeLong-span cable-supported bridges. The critical wind speed is calculated by varying the gyricity and the angular frequency of the gyroscope’s dynamical system. The results demonstrate that a multi-unit gyroscopic stabilizerGyroscopic stabilizer, within its practical operational range, can positively influence the flutter threshold of the considered long-span bridgeLong-span bridges.