The Barossa state by-election, 1933 was a by-election held on 8 July 1933 for the South Australian House of Assembly seat of Barossa. The by-election was caused by the death on 4 June 1933 of independent MP Dr Herbert Basedow, who had regained the seat at the 1933 election less than two months prior. He had previously held the seat from 1927 to 1930.
The seat was contested by four candidates: solicitor Reginald Rudall for the governing Liberal and Country League, former MP Thomas Edwards, who listed his occupation as "out of business", for the Parliamentary Labor Party, labourer Leslie McMullin for the Australian Labor Party, and farmer Lindsay Yelland as an independent. All four candidates had contested Barossa at the 1933 election. The by-election was held, as with the 1933 election, in the aftermath of the 1932 Labor split, in which the state Labor Party had split into three separate and competing parties. Edwards had been an incumbent at the time of the split, and had followed the Cabinet into the separate Parliamentary Labor Party when they were expelled over their response to the Great Depression, before his defeat by Basedow in 1933. A rumoured candidate from the third Labor splinter, the Lang Labor Party, did not emerge.
The largest booths were at Gawler (987 votes), Tanunda (774 votes), Gawler South (685 votes), Salisbury (326 votes), Angaston (375 votes) and Willaston (322 votes). There were also booths at Abattoirs, Blanchetown, Cockatoo Valley, Dublin, Enfield, Gawler Blocks, Gaza, Keyneton, Lights Pass, Loos, Long Plains, Lyndoch, Mallala, Mount McKenzie, Moculta, Northfield, Nuriootpa, Onetree Hill, Punyelroo, Red Banks, Rosedale, Roseworthy, Rowlands Flat, Sandleton, Sedan, Smithfield, St Kilda, , Stonefield, Towitta, Truro, Two Wells, Virginia, Wasleys, Wild Horse Plains, Williamstown and Windsor.