John Frederick Drummond (Jack) Jonas (circa 1881 – 2 July 1938) was an Australian politician.
He represented the South Australian House of Assembly multi-member seat of Port Adelaide from 1927 to 1933 for the Labor Party.
[3] He was educated at the Lefevre Peninsula school before leaving to work in the jarrah forests, on a cattle station and in gold prospecting at Broken Hill and in Western Australia.
[9] Jonas won the election, and continued as secretary of the Storemen and Packers' Union in tandem with his parliamentary duties.
He had shifted back to Adelaide and opened a business in Torrensville a few months before his sudden death in 1938.