Cathedral of Our Lady of Perpetual Help, Renaissance Revival cathedral in Oklahoma City, United States.

The Cathedral of Our Lady of Perpetual Help is a Renaissance Revival cathedral in Oklahoma City, Oklahoma, serving as the seat of a Roman Catholic diocese. The building features a stone facade, vaulted ceilings, and an interior lined with stained glass windows and detailed altar work.

Bishop Theophile Meerschaert assigned Monsignor Albert Monnot to found the parish on 19 January 1919; Mass was first held in a car showroom, then in a wooden church built in May 1919. The present church was begun in June 1923 and dedicated by Cardinal George Mundelein in February 1924. In November 1930 Pope Pius XI suppressed the Diocese of Oklahoma City and made this church the cathedral of the new Diocese of Oklahoma-Tulsa, replacing St. Joseph Cathedral.

The parish's name comes from the Marian title Our Lady of Perpetual Help, and its school was renamed John Carroll School in 1932 for Archbishop John Carroll of Baltimore, the first Catholic bishop in the United States. In 1975 about thirty Vietnamese refugee families joined the parish after the end of the Vietnam War, forming the core of a growing Vietnamese Catholic community.

The cathedral stands on NW 31st Street between Western and Lake, north of downtown Oklahoma City, not in the city center. The Mercy Center, which houses parish ministries and programs, was slated for a $3.5 million accessibility upgrade including an elevator, so access arrangements may change during works.

The 1924 church was dedicated by Cardinal George Mundelein, and its stained glass windows were made the same year by Emil Frei of St. Louis. In 1947, once the parish had paid off the cathedral debt, the church was consecrated and its main altar replaced with a marble one beneath a wooden baldacchino.