San Tommaso Apostolo is a Romanesque and Gothic-style, Roman Catholic church located in the town of Ascoli Piceno in the region of Marche, Italy.
Construction of the church was spurred circa 1064 by Bishop Bernardo II. The simple façade built with travertine blocks has three naves, with a tympanum with a rose window. To the right, rises a bell-tower (1283) with a square base. The church has a basilica layout with the naves and aisles separated by sturdy pilasters, and includes spolia from the former Roman amphitheater of the first century BC, which had been located in the piazza in front of the church.