William Austin Dillon (November 6, 1877–February 10, 1966) was an American songwriter and Vaudevillian. He is best known as the lyricist for the song "I Want A Girl (Just Like The Girl That Married Dear Old Dad)" (1911), written in collaboration with Harry Von Tilzer. It can be heard in Show Business (1944) and The Jolson Story (1946). He was born in Cortland, New York and performed at some point in Vaudeville with his brothers John and Harry. He billed his own act as the "man of a thousand songs".
He quit vaudeville around 1912 after injuries suffered in a car accident. Dillon died in Ithaca, New York on February 10, 1966. He married in 1918 to Georgia Leola Head, daughter of George and Mary (Steen) Head.