Original Prague Syncopated Orchestra

The Original Prague Syncopated Orchestra (Czech: Originální Pražský Synkopický Orchestr or OPSO) is a Czech band formed in Prague, in what was then Czechoslovakia, in 1974. They are best known for performing American music popular in the 1920s and 1930s, such as jazz, blues, and swing.

The initial lineup of OPSO was a five-man band consisting of three wind instruments, a piano, and a banjo, under the artistic direction of musicologist Pavel Klikar, who also founded the ensemble. Three more members joined in 1976: a second saxophone, a violin, and vocalist Ondřej Havelka. A year later, the band's roster expanded to twelve members, consisting of three reed instruments, three trumpets, a sousaphone, a banjo, a piano, two violins, and a drum kit. OPSO went on to release five studio albums and a live record in this lineup. In 1995, Havelka departed and formed his own group in Berlin, initially titled Golden Prague Syncopated Orchestra and eventually renamed Ondřej Havelka a jeho Melody Makers, also taking with him several members of OPSO. The Original Prague Syncopated Orchestra continues to perform, and they have released four more studio albums and one compilation.