The iTunes Store is a software-based online digital media store operated by Apple Inc. Opening as the iTunes Music Store on April 28, 2003, it has been the largest music vendor in the United States since April 2008, and the most popular music vendor in the world since February 24, 2010. It now offers over 28 million songs, videos and apps. The iTunes Store's revenues in the first quarter of 2011 alone totalled nearly US$1.4 billion; by October 4, 2011, the store had sold 16 billion songs.

While most downloaded files initially included restrictions on their use, enforced by FairPlay, Apple's implementation of digital rights management, iTunes later initiated a shift into selling DRM-free music in most countries, marketed as iTunes Plus. On January 6, 2009, Apple announced that DRM had been removed from 80% of the entire music catalog in the U.S. Full iTunes Plus availability was achieved on April 7, 2009 in the U.S., coinciding with the introduction of a three-tiered pricing model; however, television episodes, many books, and films are still FairPlay-protected. As of May 2012, the iTunes Store serves over 315 million mobile devices, including iPods, iPhones and iPads.