The Scottish Labour Party and Scottish Green Party both announced their candidates after nominations closed on Monday, September 13.
Labour’s candidate will be James Marshall while Stuart Duffin will be campaigning for the Greens.
They will be up against the SNP’s Emma Russell who has been on the campaign trail for weeks and the Scottish Conservative and Unionist Party candidate Sarah Patrick who has also been high profile.
Falkirk South is currently represented by SNP councillor Lorna Binnie and Conservative councillor John Patrick.
The by-election, to be held on Thursday, October 14, was caused by the resignation of Pat Reid, a former Provost of Falkirk, who had represented the ward since 2002.
Falkirk South includes Hallglen, Tamfourhill, Bantaskin and Falkirk town centre as far as Rosebank.