Tumauini Church, also known as the Church of St. Matthias, is a beautiful and historic church located in the town of Tumauini in the province of Isabela in the Philippines. It was built in the early 18th century by Spanish friars using locally sourced materials, including coral stones and bricks. The church is considered one of the best examples of Spanish colonial baroque architecture in the country, and is listed as a National Cultural Treasure by the Philippine government.

The church's main facade features a two-story design, with the ground level featuring arches and pilasters, and the upper level featuring Corinthian columns and a pediment with intricate carvings. The church also has two bell towers, each with its own dome.

Inside, the church is decorated with beautiful frescoes and paintings, as well as intricate wood carvings. The ceiling is particularly noteworthy, featuring elaborate designs that depict various biblical scenes. The church also houses a number of antique religious artifacts, including an 18th-century ivory image of the Santo Niño.

The Tumauini Church is considered one of the most important historical and cultural landmarks in the province of Isabela, and is a popular destination for tourists and pilgrims alike.