An audio adaptor (also called an audio adapter or audio adapter cable) is a small device that allows different audio equipment to connect and work together, even when their plugs or ports do not match.

Many audio devices—such as headphones, microphones, speakers, smartphones, computers, and musical instruments—use different types of audio connectors. An audio adaptor acts as a bridge between these connectors by converting one type of audio plug into another. For example, it can allow headphones with a 3.5 mm jack to be used with a device that only has a USB-C or Lightning port, or connect professional audio equipment to consumer devices.

Audio adaptors do not usually change the sound itself; instead, they ensure that the audio signal can pass correctly from one device to another. Some advanced adaptors may also include built-in electronics to convert digital audio signals to analog ones, adjust signal levels, or support microphones and controls.

In simple terms, an audio adaptor makes it possible for different audio devices to communicate, ensuring compatibility and flexibility in how audio equipment is used.