Thermae was founded in the 5th century BC by the Greeks, as its name suggests, as a thermal spa for Selinunte, 30 km distant, whose citizens came there to bathe in the sulphurous springs, still much valued for their medical properties, of Mount San Calogero which rises up behind the town.

There is no account of the existence of a town on the site during the period of the independence of Selinunte, though the thermal waters would always have attracted some population to the spot.

A royal city that had remained faithful to Manfred of Sicily during the Angevine invasion, by 1268 A.D. Sciacca was besieged by Charles I of Anjou and surrendered the following year.

In the following centuries, the town was at the center of bloody feuds between rival baronial families (the Luna, of Aragonese origin, and the Perollo, of Norman stock), which nearly halved its population.

Starting around the turn of the 20th century, a number of residents of the Sciacca area emigrated to Norristown, Pennsylvania and the North End of Boston.

holds a communion breakfast in February and a large festival (often called simply "The Feast") in August in celebration of the miracles performed by the Madonna herself in Sciacca.