Ermopouleia is the most significant festival in Syros during the summer season. It hosts an array of cultural events, musical and theatrical performances, exhibitions, and other artistic events and is organised by the Cultural Centre of Ermoupoli. It is held in venues such as the Apollo Theatre, Miaoulis Square, the Pinakothiki and the Cultural Centre.

The organization started operating in 1994 and aside from its multiple independent events, it has also executed other festivals, like the Festival of the Aegean. In 2000 the founder of the Festival of the Aegean, Peters Timboris, gave 50 young opera singers from Europe and America the opportunity to work in Greece. Since 2005, the festival has acquired a permanent home in Syros and triumphantly showcased The Barber of Seville as its first performance.