Apollo 440 (also known as Apollo Four Forty or @440) are a English electronic music group formed in Liverpool in 1990. The group has written, recorded, and produced five studio albums, collaborated with and produced other artists, remixed as Apollo 440 and as ambient cinematic alter-ego Stealth Sonic Orchestra, and created music for film, television, advertisements and multimedia. They notched up ten UK top 40 singles with three top-tens, and had a chart presence worldwide.

Its name comes from the Apollo program and the frequency of concert pitch — the A note at 440 Hz, often denoted as "A440", and the Sequential Circuits sampler/sequencer, the Studio 440. They changed the writing of their name from Apollo 440 to Apollo Four Forty in 1996, though they switched back for their latest album. To date, Apollo 440's remixes range from U2, P. Diddy/Jimmy Page, Jean-Michel Jarre and Ennio Morricone. Among their Stealth Sonic Orchestra remixes are a series of Manic Street Preachers singles.