The Church of San Sebastiano in Palazzolo Acreide has ancient origins, linked to an earlier building erected at the end of the 15th century on the site where the Church of San Rocco, built from 1414 onwards, had previously stood. Due to the expansion of the neighbourhood, the church was soon enlarged: a second structure, with a single nave, was completed in 1655. However, the devastating earthquake of 1693 completely destroyed the building along with much of the town.

At the end of the 17th century, construction began on the present church, still dedicated to Saint Sebastian and built in the basilica style. The design of the monumental façade was entrusted to the Syracusan architect Mario Diamante, assisted by local master builders such as Milito and Buscema; work was completed around 1782, following a long and complex construction phase.

The façade, approximately 35 metres high and built from Iblean cut stone, is one of the most spectacular examples of Sicilian Baroque. It is organised into three superimposed orders, enriched with architectural elements in the late Renaissance style. The first order is dominated by an elegant portal framed by paired Corinthian columns and decorated at the base by two stone lions sculpted by Diamante himself. Above the portal, in a niche, stands the statue of the saint. The second order houses a large clock, whilst the third is characterised by the bell loggia with its bells and a weather vane crowning the top.

The church overlooks Piazza del Popolo, helping to define its dramatic layout alongside the surrounding buildings. Access is made all the more striking by the grand staircase built in 1877, which connects to the road network linking the main squares of the historic centre.

The interior features a longitudinal plan with three naves, with two chapels at the ends of the side aisles, creating a spacious and solemn space that reflects the building’s religious and artistic significance.