Isabel, is a private Catholic university run by the Sisters of Charity of Saint Vincent De Paul in Naga, Camarines Sur, Philippines.

Francisco Gainza, O.P., Bishop of Caceres, in 1868 as the first normal school for women in the Philippines and Southeast Asia, named in honor of the university's patron, St. Isabel, Queen of Hungary.

The administration of the school was given to six Daughters of Charity sisters who arrived in the Bicol Region (Philippines) on April 4, 1868.

A Royal Decree of Queen Isabella II of Spain, dated January 11, 1872, granted to the Lord Don Fray Francisco Gainza, Bishop of Nueva Caceres, the authority to construct a school for girls (escuela de niñas) which will be under the care of the Hijas de Caridad (Daughters of Charity).

Isabel is now also known as the Heritage and Historical University of Bicol At the unveiling ceremony of the historical marker, NCHP Chairman Dr. Rene R. Esclante said that "USI is important in the history of the Philippines as this is the oldest school in the country," and "the first normal school for women built during the Spanish era, where traces of the old structures and even the courses offered still exists as to this time."