Ktiš (German: Tisch) is a municipality and village in Prachatice District in the South Bohemian Region of the Czech Republic. It has about 500 inhabitants.

Ktiš consists of nine municipal parts (in brackets population according to the 2021 census):

The origin of the name is unsure. The initial name of the village was probably Choťúš, meaning "Choťouch's (court)", and the name Ktiš evolved from Choťúš.

Ktiš is located about 14 kilometres (9 mi) southeast of Prachatice and 25 km (16 mi) west of České Budějovice. It lies mostly in the Bohemian Forest Foothills, only the westernmost part of the municipality extends into the Bohemian Forest. The highest point is the mountain Ktišská hora at 911 m (2,989 ft) above sea level.

The stream Křemžský potok flows through the municipality. The upper course of the stream Bezdrevský potok crosses the municipality in the north. The territory of Ktiš is rich in small streams and fishponds. In the east, the municipality extends into the Blanský les Protected Landscape Area.

Ktiš's climate is classified as humid continental climate (Köppen: Dfb; Trewartha: Dclo). Among them, the annual average temperature is 7.4 °C (45.3 °F), the hottest month in July is 16.8 °C (62.2 °F), and the coldest month is −1.5 °C (29.3 °F) in January. The annual precipitation is 804.6 millimetres (31.68 in), of which June is the wettest with 111.5 millimetres (4.39 in), while December is the driest with only 42.6 millimetres (1.68 in). The extreme temperature throughout the year ranged from −23.4 °C (−10.1 °F) on 3 February 2012 to 33.8 °C (92.8 °F) on 7 August 2015.

The first written mention of Ktiš is from 1310, when the church already stood there.

There is a deposit of garnet migmatites in the municipality, the only one in the European Union. Mining took place here in 1994–1996 and its resumption was considered in 2012.