Radio programming is the content that is broadcast by radio stations.

The original inventors of radio, such as Nikola Tesla and Guglielmo Marconi, expected it to be used for one-on-one communication tasks where telephones and telegraphs could not be used because of the impossibility of stringing wires from one point to another, such as in ship-to-shore communications. These inventors had no expectations whatever that radio would become a major mass entertainment and information medium earning many millions of dollars in revenues annually through commercial sponsorship. These latter uses were brought about after 1920 by business entrepreneurs such as David Sarnoff, who created the National Broadcasting Company (NBC), and later William S. Paley, who built the Columbia Broadcasting System (CBS). These broadcasting (as opposed to narrowcasting) business organizations began to be called networks, because they consisted of loose chains of individual stations located in various cities, all transmitting the standard overall-system supplied fare, often at synchronized agreed-upon times. Some of these stations were owned by the networks, while others were owned by independent businessmen allied with the respective networks. By selling blocks of time to advertisers for commercial announcements, the medium was able to quickly become profitable and offer its products to listeners for free, provided they invested in a radio receiver set. The new medium grew extremely quickly though the 1920s, vastly increasing both the size of its audience and its profits. In these early days, it was customary for a corporation to sponsor an entire half-hour radio program, placing its commercials at the beginning and the end. This is in contrast to the pattern which developed late in the 20th century in both television and radio, where small slices of time were sold to many sponsors and no corporation claimed or wanted sponsorship of the entire show, except in rare cases. These later commercials also filled a much larger portion of the total program time than they had in the earlier days.

In the early radio age, content typically included a balance of comedy, drama, news, music and sports reporting. U.S. radio programs included the most famous Hollywood talent of the day. Radio soap operas began in the U.S. in 1930 with Painted Dreams. Despite radio's majority use being spoken entertainment, the Grand Ole Opry, as of 2006 being the longest-running radio program, has been focused on broadcasting country music since it began in 1925.

In the late 1940s and early 1950s, television eroded the popularity of radio comedy, drama and variety shows. By the late 1950s, radio broadcasting took on much the form it has today — strongly focused on music, news and sports, though drama can still be heard, especially on the BBC.

In Britain during the 1950s, radio broadcasting was dominated entirely by the BBC. Rock and pop music fans, dissatisfied with the BBC's output, often listened to Radio Luxembourg. During the post-1964 period, western Europe offshore radio (such as Radio Caroline broadcasting from ships at anchor or abandoned forts) helped to supply the demand for the pop and rock music. The BBC launched their own pop music station, BBC Radio 1 in 1967.