Robert John Daisley (born 13 February 1950) is an Australian musician and songwriter. A bass guitarist, he is perhaps best known for his intermittent relationship with vocalist Ozzy Osbourne, for whom he contributed bass, co-production and songwriting throughout the 1980s. Daisley has also worked with prominent rock acts including Black Sabbath, Rainbow, Gary Moore, Chicken Shack and Uriah Heep, among others. In 2013, he published his autobiography entitled For Facts Sake which has received outstanding reviews.