Robert Steven "Adrian" Belew (born December 23, 1949) is an American musician, singer, songwriter, and record producer. A multi-instrumentalist primarily known as a guitarist and singer, he is noted for his unusual approach to the instrument, his playing often resembling sound effects or noises made by animals and machines.

Widely recognized as an "incredibly versatile [guitar] player", Belew is perhaps best known for his tenure as guitarist and frontman in the progressive rock group King Crimson between 1981 and 2009. He has also released nearly twenty solo albums for Island Records and Atlantic Records in various styles. In addition, Belew has been a member of the intermittently active band the Bears, and fronted GaGa in the late 1970s and early 1980s.

Belew has also worked extensively as a session, guest, and touring musician, including periods with Frank Zappa, David Bowie, Talking Heads, Laurie Anderson, and Nine Inch Nails, as well as contributing to hit singles by Paul Simon, Tom Tom Club, and others. His 1989 solo single "Oh Daddy" was a top ten hit in the United States, and his 2005 single "Beat Box Guitar" was nominated for a Grammy Award for Best Rock Instrumental Performance. Belew has also worked in instrument design and multimedia, collaborating with Parker Guitars to help design his Parker Fly signature guitar, and designing two iOS mobile apps.