Ivan Peter Lewis (1 January 1942 – 26 September 2017) was an Australian politician.
Lewis was a member of the South Australian House of Assembly between 1979 and 2006 in the electorates of Hammond, Ridley, Murray-Mallee and Mallee.
From 1979 he was in the House as a Liberal member, however he was expelled from the Liberals in 2000.
He was re-elected as an independent, serving until 2006.
His decision to serve as Speaker of the South Australian House of Assembly for a Labor government resulted in Mike Rann becoming Premier of South Australia from the 2002 election.
His death was reported on 28 September 2017 to have been earlier in the week, in Sydney.