Abstract: A mud flap stabilizer device is for use with an elongate, generally rectangular mud flap formed of flexible material and swingably supported adjacent its upper end from a vehicle body rearwardly of and in close proximity to a vehicle wheel mounted tire. The stabilizer device includes a frame body with a hanger member extending upwardly therefrom and connected to a normally horizontally extending bar member in a depending relationship. The bar member is swingably mounted to the vehicle body rearwardly of the mud flap whereby the frame body is positioned against the mud flap. Rotation limiting arms control swinging movement of the frame body to limit movement of the mud flap. Illumination members such as reflectors or electrical lamps are connected to the frame body for visual enhancement.