William Joseph "Bill" Denny, MC (6 December 1872 – 2 May 1946) was a South Australian journalist, lawyer, politician and decorated soldier who held the South Australian House of Assembly seats of West Adelaide from 1900 to 1902 and then Adelaide from 1902 to 1905 and again from 1906 to 1933. After an unsuccessful candidacy as a United Labor Party (ULP) member in 1899, he was elected as an "independent liberal" in a by-election in 1900. He was re-elected in 1902, but defeated in 1905. The following year, he was elected as a ULP candidate, and retained his seat for that party (the Australian Labor Party from 1917) until 1931. Along with the rest of the cabinet, he was ejected from the Australian Labor Party in 1931, and was a member of the Parliamentary Labor Party until his electoral defeat