Collegiate Church of St. Secondus, Gothic collegiate church in Piazza San Secondo, Asti, Italy

The Collegiate Church of St. Secondus has a longitudinal plan with three irregular naves, the central one wider and ending in a pentagonal apse; the left nave ends in a flat apse and the right in a circular one. The facade follows the Romanesque gable form divided into three parts, with a brick rose window in the centre. The Romanesque bell tower survives from the earlier building.

This building was founded in 1256 to replace an older church that had stood outside the city walls since the 9th century. The relocation into the urban center reflected the community's growing need for a central place of worship.

The chapel of San Secondo, at the right of the presbytery, was frescoed by Golzio in 1779 and permanently displays fifteen ancient Palii (1700–1870) bearing the saint on horseback and the Savoy arms, plus ten silk banners from the 1600s, the oldest in Asti, showing scenes of his life.

The church faces Piazza San Secondo beside the town hall, with the main entrance on the facade and side doors from the 16th century. The Cappella di San Secondo, at the end of the right side of the presbytery, holds the Palii and banners on display all year. The crypt, with its 6th-7th century columns, lies below.

A chapel in the right aisle houses the Carroccio, a historic wagon used during the annual Palio festival of Asti. This vehicle directly connects the sanctuary to one of the city's most important popular celebrations.