Štefan Miroslav "Mirko" Messner (born 16 December 1948)[1] is an Austrian, Carinthian Slovene Slavicist and communist politician, leading the Communist Party of Austria (KPÖ) from February 2006 to June 2021.

[1] As a teenager, he was politically active in the Verband Sozialistischer Mittelschüler (Association of Socialist Middle Schoolers) in Carinthia.

[6] After the KPÖ held the Grazer Erneuerungsparteitag (Party Congress for Renewal in Graz) in 2005, Messner was initially active in the reconstitution of the KPÖ in Klagenfurt and was finally elected as the party's minority spokesman and a member of its federal executive board in February 2006.

In March of the same year, Messner was also elected Federal Spokesperson for the party together with Melina Klaus.

Messner has been the leading candidate for his party in all four Austrian National Council elections since 2006.