Internet radio is a digital audio service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means. It can either be used as a stand-alone device running through the Internet, or as a software running through a single computer.

Internet radio involves streaming media, presenting listeners with a continuous stream of audio that typically cannot be paused or replayed, much like traditional broadcast media; in this respect, it is distinct from on-demand file serving. Internet radio is also distinct from podcasting, which involves downloading rather than streaming.

Internet radio services offer news, sports, talk, and various genres of music—every format that is available on traditional broadcast radio stations. Many Internet radio services are associated with a corresponding traditional (terrestrial) radio station or radio network, although low start-up and ongoing costs have allowed a substantial proliferation of independent Internet-only radio stations.

The first Internet radio service was launched in 1993. As of 2017, the most popular Internet radio platforms and applications in the world include (but are not limited to) TuneIn Radio, iHeartRadio, and Sirius XM.