Bob Daisley (born February 13, 1950, in Sydney, Australia) is a renowned bassist, songwriter, and lyricist whose career spans over five decades. He is best known for his extensive work with Ozzy Osbourne, which contributed significantly to Osbourne's early solo success.

Daisley began his musical journey in the 1960s, initially playing guitar before switching to bass at age 14. He gained early recognition with bands like Kahvas Jute and Chicken Shack. In the mid-1970s, he co-founded Widowmaker and later joined Ritchie Blackmore's Rainbow, contributing to their 1978 album Long Live Rock 'n' Roll.

His most notable collaboration was with Ozzy Osbourne, starting in 1979. Daisley played bass, co-wrote songs, and co-produced several of Osbourne's albums, including Blizzard of Ozz (1980) and Diary of a Madman (1981). Despite being replaced before the release of Diary of a Madman, Daisley's performances remained on the album, leading to legal disputes over credits and royalties. He continued to work intermittently with Osbourne throughout the 1980s and early 1990s, contributing to albums like Bark at the Moon (1983) and No More Tears (1991).

Beyond his work with Osbourne, Daisley collaborated with several prominent artists and bands, including Uriah Heep, Gary Moore, and Black Sabbath. He was involved in projects like Mother's Army (with Joe Lynn Turner, Carmine Appice, Ansley Dunbar & Jeff Watson) and Living Loud, all showcasing his versatility across genres from blues to hard rock.

In 2013, Daisley published his autobiography, For Facts Sake, detailing his experiences in the music industry. He continues to be recognized for his influential role in shaping the sound of classic rock and heavy metal.