Automobile brake squeal noise, which is nonlinear, friction-induced vibration in the frequency range of 1kHz~16kHz, still remains a serious issue for the automobile industry. This paper presents experimental investigations into the suppression of automobile disc brake squeal noises using dither control. Dither control is a concept of active noise control by introducing high-frequency actuation into a system to suppress lower-frequency disturbance such as brake squeal noise. A dither control system for noise suppression was designed considering impedance matching and built for a real car application. The dither force was generated by a piezoelectric stack actuator in the piston of a floating caliper brake. Our experimental results indicate that dither control could effectively suppress the brake squeal noise in a real car.