Church of Saint John the Baptist, Catholic church ruin in Janov, Czech Republic.

The Church of Saint John the Baptist is a stone ruin in Janov with Gothic and Baroque architectural features visible on its weathered exterior walls. The structure still shows details of its original religious design despite standing abandoned today.

A first shrine may have stood here in the 11th century; German miners possibly built a church of St John the Baptist in the 13th century, and a 1578 record mentions a service led by the priest from Brod nad Tichou. The Baroque church was built in 1728–1732 at the expense of Count Václav ze Sinzendorfu and consecrated on 24 June 1732 by the Kladruby abbot Siebert. Closed in 1781 under the Josephine reforms, it was protected as a Czech cultural monument from 1992.

The church stood in the now-vanished settlement of Sankt Johann (Sv. Jan), which still had 92 inhabitants in 1921. In 1801, school rector Karel Okl staged Joseph Haydn's oratorio "The Creation" inside the locked church, showing that devotion to the site continued after its 1781 closure.

The ruin stands south of Kočov in the former settlement of Sankt Johann, now vanished, in the Tachov district. The facade was dismantled to its foundations and part of the vault collapsed after 2000 filming, so the masonry is unstable; approach with care and do not enter the interior.

In 2000 the ruin was dressed as a hellish cavern for Zdeněk Troška's fairy-tale film Z pekla štěstí 2; the last remains of the Baroque paintings disappeared during the shoot, and soon afterwards much of the vault collapsed.