Tillmitsch is a municipality in the district of Leibnitz, in the Austrian state of Styria. It lies in the southern part of Styria, a region known as the Leibnitz district, which is part of the broader area of southern Austria bordering Slovenia.
The municipality is one of several small communities that make up the Leibnitz district, an area characterised by its rural landscape and proximity to the city of Leibnitz, the district's administrative centre. Like many municipalities in this part of Styria, Tillmitsch is a scattered settlement rather than a single dense town, comprising a number of small villages and hamlets within its boundaries.
Southern Styria, where Tillmitsch is located, is known for its rolling hills, vineyards and agricultural land, and the region forms part of Austria's wine-growing area. The municipality's position in the Leibnitz district places it within easy reach of the regional centres of Graz, the Styrian capital, and the nearby border with Slovenia.