Karlovy Vary (Czech pronunciation: [ˈkarlovɪ ˈvarɪ] ; German: Karlsbad, formerly also spelled Carlsbad in English) is a spa city in the Karlovy Vary Region of the Czech Republic. It has about 49,000 inhabitants. It is located at the confluence of the Ohře and Teplá rivers.

Karlovy Vary is named after Charles IV, Holy Roman Emperor and the King of Bohemia, who founded the city in the 14th century. The site of numerous hot springs, the city grew into a spa resort in the 19th century and was a popular destination for the European aristocracy and other luminaries. Karlovy Vary's rapid growth was brought to an end by the outbreak of World War I. After the Velvet Revolution in 1989, Karlovy Vary once again became a major tourist destination.

Karlovy Vary is the most visited spa town in the Czech Republic. In 2021, the city became part of the transnational UNESCO World Heritage Site under the name "Great Spa Towns of Europe" because of its spas and architecture from the 18th through 20th centuries. The historic city centre with the spa cultural landscape is well preserved and is protected as an urban monument reservation.