Kar(e)l Faustin Klostermann (13 February 1848 in Haag am Hausruck, Upper Austria, Austrian Empire – 17 July 1923 in Štěkeň, Czechoslovakia) was a Czech and Austrian writer. He wrote under the alias Faustin.
From 1857 to 1865 he went to school in Písek, a town in the South Bohemian Region of what is now the Czech Republic. He studied medicine until 1869 in Vienna, and was later active as a teacher of German and French at the German high school in Plzeň. He first wrote his works in German; later he turned to the Czech language and wrote novellas about the inhabitants of the middle Bohemian Forest (Czech: Šumava, German: Böhmerwald). This can be found in the collection V srdci šumavských hvozdů ("In the heart of the Šumava"). Some of his novellas are set in and around the town of Kašperské Hory.
- Ze světa lesních samot (From the world of forest solitude) - 1891
- Syn svobodného soudce (The son of the free judge)
- Pěst v příbězích (Fist in stories)