Dragnet was a long running NBC radio and television show about the cases of a Los Angeles, California police detective, Joe Friday, and his partner. It first aired on the radio on June 3, 1949 and began its television run on December 16, 1951.

The show was created and produced by Jack Webb, who also starred as Sgt. Friday. It was advertised as a true-crime police show, told from the point of view of a hard-bitten detective on the Los Angeles police force. It's said that Webb hung out at police headquarters and attended classes at the police academy to help him bring authenticity to the show.

On every broadcast, the announcer stated that "The story you are about to hear is true. Only the names have been changed, to protect the innocent." "Hear" was changed to "see" for the television version.

Dragnet first appeared on television in January of 1952. Friday's original partner in the TV episodes (as on the radio) was Sgt. Ben Romero, played by Barton Yarborough, who died after only three episodes were filmed. The Romero character was soon replaced by Officer Frank Smith, played by Ben Alexander. Alexander continued in the role through the show's original run, which ended in 1959. While Dragnet was still on the air, reruns began to air in syndication as Badge 714. In 1954, a theatrical movie of the same name aired, with Webb, Alexander, and Richard Boone.

In 1966, a TV movie, also called Dragnet, aired. Starring Jack Webb and Harry Morgan as his partner Bill Gannon, it spawned a new series, Dragnet 1967, which aired until 1970, the title year changing with each season.

In 1987, a comedy movie version of Dragnet appeared, starring Dan Aykroyd as the stiff Joe Friday (the original Detective Friday's nephew), and his partner Pep Streebeck, played by Tom Hanks.

In 1997, The New Dragnet appeared in first-run syndication, and in 2003 yet another Dragnet series was produced by Dick Wolf, the producer of Law & Order. The most recent version starred Ed O'Neill as Joe Friday.