David John O'Keefe (21 August 1864 – 21 July 1943) was an Australian politician.
Born in Longford, Tasmania, he was educated at state schools before becoming a farm worker and miner. He was involved in the labour movement as a journalistand an organiser of the Australian Workers' Union.
In 1901, he was elected to the Australian Senate, running with endorsement from the Protectionist Party, as there was no Labour Party in Tasmania at the time; however, he joined the Australian Labor Party caucus in Parliament.
He was defeated in 1906, but re-elected in 1910, serving until his defeat in 1919 (taking effect in 1920).
In 1922, he was elected to the House of Representatives, defeating Labor-turned-Nationalist MP William Laird Smith for the seat of Denison. He was the first Tasmanian to have served in both houses of federal parliament.
He was defeated in 1925 by Nationalist Sir John Gellibrand and worked in Western Australia for some time before returning to Tasmania in 1931. In 1934 O'Keefe was elected to the Tasmanian House of Assembly, immediately taking the position of Speaker. He held the Speaker's position until 1942 and died the following year.