John Peter Sim, (21 June 1917 – 29 July 2015) was an Australian politician.
Born in Colac, Victoria, he was a farmer in Western Australia before serving in the military 1941–1946.
He was Vice-President of the Western Australian Liberal Party 1960–1962.
On 26 November 1964, he was appointed to the Australian Senate as a Liberal Senator for Western Australia, filling the casual vacancy caused by the death of Senator Seddon Vincent.
He held the seat until his retirement in 1980.
Sim was appointed a Commander of the Order of the British Empire (CBE) on 31 December 1982, for service to parliament.Sim died on 29 July 2015.