Semafor is a Czech theatre in Prague established by Jiří Suchý and Ferdinand Havlík in 1959. It belongs to the so-called "Theatres of small stages". Suchý himself has performed there for many years and is the current owner. The Semafor theatre was a starting point for many famous Czech musicians such as Karel Gott and Hana Hegerová.
The name "Semafor" itself, is abbreviation for Sedm Malých Forem (Seven Small Forms) making reference to form of theater.