Internet radio (also known as web radio, net radio, streaming radio and e-radio) is an audio broadcasting service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means. Internet radio involves a streaming medium that presents listeners with a continuous "stream" of audio to which they have no control, 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. Many Internet radio "stations" are associated with a corresponding traditional (or "terrestrial") radio station or radio network. Internet-only radio stations are independent of such associations.

Internet radio services are usually accessible from anywhere in the world—for example, one could listen to an Australian station from Europe or America. This makes it popular among expatriates and listeners with interests that are often not adequately served by local radio stations (such as progressive rock, ambient music, anime-themed music, classical music, and stand-up comedy). Internet radio services offer news, sports, talk, and various genres of music—everything that is available on terrestrial radio stations.