William, Willie or Billy Dunn may refer to:
- William Dunn (physician) (c.1550-1607), English physician, President of Royal College of Physicians.
- William Dunn (industrialist) (1770-1849), mechanic and agriculturist
- William Dunn (Medal of Honor) (1834-1902), American Civil War sailor
- Sir William Dunn, 1st Baronet, of Clitheroe (1856-1926), British Conservative politician
- Sir William Dunn, 1st Baronet, of Lakenheath (1833–1912), London banker, merchant and philanthropist, Liberal Member of Parliament for Paisley
- William E. Dunn, former mayor of Murray, Utah, and county commissioner
- William M. Dunn (1814–1887), U.S. Representative from Indiana
- William Dunn (footballer) (born 1877), English footballer, played for Manchester United.
- William R. Dunn (1916–1995), American World War II fighter pilot
- William Thomas Dunn, All-American football player for Penn State
- William Dunn, a fictional character in the Blue Tracer comic book series
- Willie Dunn, Canadian filmmaker, folk musician, playwright and politician
- Billy Dunn (footballer born 1865) (died 1921), Scottish footballer with Stoke and other clubs
- Billy Dunn (footballer born 1910) (died 1980), Scottish footballer with Celtic, Brentford, Southampton and other clubs
Famous quotes containing the words billy and/or dunn:
“Waltzing Matilda, Waltzing Matilda,
Who’ll come a-waltzing Matilda with me?
And he sang as he watched and waited while his billy boiled:
‘Who’ll come a-waltzing Matilda with me?’”
—Andrew Barton Peterson (1864–1941)
“Harry’s an artist without an art ... groping for the right lever, for the means with which to express himself.”
—Jo Eisinger, and Jules Dassin. Adam Dunn (Hugh Marlowe)