KEF is a British loudspeaker manufacturer founded in 1961 in Maidstone, Kent by former BBC engineer Raymond Cooke. The company name is an acronym for Kent Engineering & Foundry, after the metalworks on whose grounds the original factory was built. Cooke's interest in synthetic cone materials shaped the company's early identity, and KEF drivers — notably the B110 mid-bass and T27 tweeter — were selected by the BBC for use in the LS3/5a, the compact monitor that became a long-running standard in broadcast and small-room studio listening.

KEF is best known for its Uni-Q driver array, a coincident design that places the tweeter at the acoustic center of the mid/bass cone so the entire driver behaves as a point source. The technology runs through most of the company's catalog, including the LS50 and LS50 Meta bookshelf monitors, the LS50 Wireless II and LSX active systems, the floorstanding R Series and Reference Series, and the Blade and Muon flagships. Alongside passive hi-fi speakers, KEF produces wireless and streaming-capable models, in-wall and architectural speakers, soundbars, and headphones.

While KEF is primarily a high-end home audio brand rather than a pro-audio manufacturer, models like the LS50 are used by some musicians and engineers as nearfield reference monitors, and the company's BBC-derived monitor lineage gives it a foothold in the recording world. KEF is owned by the Hong Kong–based Gold Peak Group, which acquired it in 1992, but design and engineering remain based in Maidstone.

KEF has 9 products cataloged on Equipboard, including Active & Passive Monitors, Music Stands, and Home Subwoofers. Their gear is featured by 2 artists, with the strongest followings in Electronic, Rock, and Pop. Notable users include Luca Pretolesi and Hisham Farouq.