Opera Theatre of Saint Louis (OTSL) is a summer opera festival held in St. Louis, Missouri. Typically four operas, all sung in English, are presented each season, which runs from late May to late June. Performances are accompanied by the St. Louis Symphony Orchestra, which is divided into two ensembles, each covering two of the operas, for the season. The company's performances are presented in the Loretto-Hilton Center for the Performing Arts on the campus of Webster University. In 2005, OTSL adopted projected English-language supertitles in the theatre.