A portable media player (PMP) or digital audio player, (DAP) is a consumer electronics device that is capable of storing and playing digital media such as audio, images, video, documents, etc. the data is typically stored on a hard drive, microdrive, or flash memory. In contrast, analog portable audio players play music from cassette tapes, or records. Often digital audio players are sold as MP3 players, even if they support other file formats. Other types of electronic devices like cellphones, internet tablets, and digital cameras are sometimes referred as PMPs because of their playback capabilities. This article focuses on portable devices that have the main function of playing media.

The immediate predecessor in the market place of the digital audio player was the portable CD player and prior to that, the personal stereo.

British scientist Kane Kramer designed one of the earliest digital audio players, which he called the IXI. His 1979 prototype was capable of approximately one hour of audio playback but it did not enter commercial production. His UK patent application was not filed until 1981.Apple Inc. hired Kramer as a consultant and presented his work as an example of prior art in the field of digital audio players during their litigation with Burst.com almost two decades later.

Audio player refers to a device or application that is capable of playback of audio data. In the strict sense of the term any device capable of audio playback falls under this category, although usually only digital equipment or software is meant.

Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), digital storage, processing and transmission components. A primary benefit of digital audio is in its convenience of storage, transmission and retrieval.

Digital audio is useful in the recording, manipulation, mass-production, and distribution of sound. Modern distribution of music across the Internet via on-line stores depends on digital recording and digital compression algorithms. Distribution of audio as data files rather than as physical objects has significantly reduced the cost of distribution.

In an analog audio system, sounds begin as physical waveforms in the air, are transformed into an electrical representation of the waveform, via a transducer (for example, a microphone), and are stored or transmitted. To be re-created into sound, the process is reversed, through amplification and then conversion back into physical waveforms via a loudspeaker. Although its nature may change, analog audio's fundamental wave-like characteristics remain the same during its storage, transformation, duplication, and amplification.