The patrons of Gradisca d'Isonzo are Saints Peter and Paul, celebrated on 29 June.
The town hosts the Chocofest, the largest chocolate-themed festival in the region, and the Ethnicfest, dedicated to culinary traditions from around the world. Every third Sunday of the month, the «Alpe Adria» antiques and second-hand market is also held. The town also holds the Cathedral of Gradisca d'Isonzo and the Castle of Gradisca d'Isonzo.