A car stereo is a device that can be in a car to listen to the radio, play cassettes or CDs. More modern car stereos can also play music from memory sticks.

Car stereos typically can not produce much power without circuit which makes the car's battery voltage higher. Often car speakers have lower impedance. Then it is easier to get more audiopower without having higher voltage.

Initially implemented for listening to music and radio, vehicle audio is now part of car telematics, telecommunication, in-vehicle security, handsfree calling, navigation, and remote diagnostics systems. The same loudspeakers may also be used to minimize road and engine noise with active noise control, or they may be used to augment engine sounds, for instance making a smaller engine sound bigger.