Basilica of San Lorenzo, Gothic basilica in Mortara, Italy

The Basilica of San Lorenzo is a Gothic church in Mortara with a brick facade, a central rose window, and lateral pointed windows framed by buttresses. The structure displays typical features of Italian Gothic architecture, with these design elements extending upward to the roof.

The Gothic basilica was built between 1375 and 1380, possibly by Bernardino (Bartolino) da Novara. In 1443 the minor portal was altered, and in 1573 Martino Bassi made structural changes. Restoration followed under Epifanio Fagnani from 1829 to 1840, and in 1916 Giulio d'Andreade and Cesare Bertea restored the facade and one side.

The wooden Nativity scene is by Andrea da Milano, not a local artist. The first chapel on the right holds Bernardino Lanino's Madonna del Rosario with Saints and Devotees (1579), commissioned by the Rosary Confraternity; it records the Virgin's intervention at the Battle of Lepanto on 7 October 1571, with Pius V, Don John of Austria and Marcantonio Colonna among the figures, and the two fleets shown in a roundel on the predella.

The church is the seat of the diocese of Vigevano and the main place of worship in Mortara. The interior is a Latin cross measuring 49 by 19.5 metres, with three naves; the Madonna delle Grazie fresco is immediately on the right after entering, and the altars of the second chapel and the end wall follow along the right side.

The two 15th-century reliefs above the main portal are not the only old carvings on the facade: the roundels (tondi) are by Boniforte da Mortara, and Nando Bialetti painted the lunettes, including a Deposition over the minor portal recalling the demolished chapel of the Pietà that once stood where the side entrance is now.