The Cathedral of Saint Tryphon is a Roman Catholic cathedral and the seat of the Catholic Bishopric of Kotor, located within the fortified Old Town of Kotor, Montenegro. It is dedicated to Saint Tryphon, the patron saint of the city, and stands as one of the most significant and recognizable monuments of medieval architecture on the Adriatic coast.

The cathedral's history dates to the 12th century. According to tradition, the original church was constructed in 809 to house the relics of Saint Tryphon, which were acquired by a local citizen. The present Romanesque structure was consecrated in 1166, following a major reconstruction initiated after an earthquake damaged the earlier building. The cathedral has undergone numerous modifications and restorations over the centuries due to seismic activity, which has influenced its architectural appearance.

Architecturally, the cathedral is a notable example of Romanesque architecture with later Gothic, Renaissance, and Baroque additions. The building features a characteristic two-tower facade, though the towers are not symmetrical due to different completion dates and subsequent reconstructions. The interior is organized as a basilica with three naves, separated by columns with Romanesque capitals. The main altar houses a richly decorated stone ciborium, a masterpiece of Romanesque sculpture from the 14th century.

The cathedral treasury is of immense historical and artistic value. It contains a collection of sacred art, including silver and gold reliquaries, liturgical vessels, manuscripts, and vestments, many dating from the 12th to the 18th centuries. These artifacts reflect the wealth and cultural importance of Kotor as a major maritime and trading center of the medieval Adriatic.

As a religious and cultural landmark, Saint Tryphon's Cathedral has played a central role in the life of Kotor for centuries. It is a key site for the annual celebration of the Feast of Saint Tryphon on February 3rd, which is a major event for the city. The cathedral is also a protected cultural monument and, as part of the Natural and Culturo-Historical Region of Kotor, is inscribed on the UNESCO World Heritage List.