Flatschach is a former municipality in the district of Murtal, in the Austrian state of Styria. It is located in the Murtal region of central Austria, within the federal state of Styria (Steiermark).
As part of the 2015 Styria municipal structural reform, Flatschach ceased to be an independent municipality and was incorporated into the municipality of Spielberg. Since that reform, it has been a constituent part of Spielberg rather than a separate administrative unit.
Its administrative history is therefore defined chiefly by this merger, which placed the former municipality within the larger municipal structure of Spielberg in the Murtal district.