Ostrov is a town in Karlovy Vary District in the Karlovy Vary Region of the Czech Republic. It has about 16,000 inhabitants. The historic town centre is well preserved and is protected by law as an urban monument zone.

The Karlovy Vary Region or Carlsbad Region is an administrative unit of the Czech Republic, located in the westernmost part of its historical region of Bohemia. It is named after its capital Karlovy Vary. Spas in the region include Karlovy Vary and Mariánské Lázně.