Heather Southcott (November 15, 1928 – 21 November 2014) was an Australian politician, representing the electoral district of Mitcham (now Waite) in the South Australian House of Assembly for the Australian Democrats.
The seat was won by Southcott and the Democrats at the 1982 Mitcham by-election, resulting from the resignation of Robin Millhouse, who represented the seat since its creation in 1955. While Millhouse originally represented the Liberal and Country League (the predecessor to the Liberal Party of Australia in South Australia), disagreement within the party over social policy direction and electoral reform saw him leave the party in 1973 to assist in the formation of the Liberal Movement, which became the New LM in 1976, which then became the Australian Democrats in 1977, and continued with the Democrats until his resignation from parliament in 1982. Southcott lost the seat at the 1982 state election to Stephen Baker from the moderate faction of the Liberal Party.
- "Vale Heather Southcott AM First woman to lead a political party in Australia". australian-democrats.org.au. November 23, 2014.