Wayne Ian Duncan (31 May 1944 – 4 December 2016) was an influential Australian rock musician known for his role as a bass guitarist and backing vocalist. Born in Preston, Victoria, Australia, Duncan's music career spanned from 1959 to 2016. He was a founding member of the iconic doo-wop band Daddy Cool, which was inducted into the ARIA Hall of Fame in 2006. Throughout his career, Duncan was also part of several other bands, including The Rondells, Sons of the Vegetal Mother, Gary Young's Hot Dog, Jane Clifton and the Go Go Boys, the Black Sorrows, and the Hornets.

Duncan's early musical journey began in instrumental groups like the Ramrods and the Lincolns. He and Gary Young formed the rhythm section for numerous Melbourne-based bands starting in 1963. The Lincolns, which later became known as the Rondells, backed the popular duo Bobby & Laurie, achieving a No. 1 hit with "Hitch Hiker" in 1966. Duncan's inventive bass playing was noted by music journalist Ian McFarlane, highlighting his dynamic contribution to the latter-day material of Daddy Cool.

In late November 2016, Duncan suffered a stroke and passed away a week later in Melbourne. He was survived by his domestic partner, Anne, and two children.