Abstract: Previous studies have shown that helical wires are effective in mitigating rain-wind-induced vibration of stay cables. However, the suppression efficacy and the mechanism regarding vortex-induced vibration (VIV) remain unclear, especially when considering the cable’s inclination and yaw angles. Using synchronous vibration and pressure measurement wind tunnel tests on stay cable segment models, double helical wires with a pitch of 3.14D and different diameters were employed to investigate the VIV responses and wind pressure distribution characteristics of stay cables under different yaw angles at an inclined angle of 25°. The study results show that: under the same absolute yaw angle, the VIV amplitude is larger when the oncoming flow approaches from the upper end of the cable than that when it approaches from the lower end. The double helical wires with a diameter of 0.07D exhibit limited suppression effects at small pitches, whereas they demonstrate better performance at large pitches. Double helical wires with a diameter of 0.10D can effectively suppress the VIV of stay cables at different yaw angles with an amplitude suppression rate exceeding 50%. Helical wires induce the early separation of the circumferential flow and reduce the spanwise correlation of surface wind pressures to weaken the spanwise strength of vortex shedding, thereby suppressing vortex-induced vibration.