St. Louis Cathedral, Catholic cathedral in French Quarter, New Orleans, United States.

St. Louis Cathedral is a Catholic cathedral in the French Quarter of New Orleans, United States, standing directly on Jackson Square with its white facade facing the open plaza. The three spired towers rise above the nave, while large arched windows line the side walls in a regular arrangement that brings light into the interior.

A first wooden church was built on this site in 1718, when New Orleans was founded; a larger brick and timber church, begun in 1725 and finished in 1727, burned in the Good Friday fire of March 21, 1788. The cornerstone of a new church was laid in 1789 and the building was completed in 1794 under Spanish rule, becoming a cathedral in 1793. Rebuilt in the 1850s to plans by Jacques Nicolas Bussière de Pouilly, it lost most of the Spanish colonial fabric; the present structure dates mainly to 1850.

The cathedral is dedicated to Saint Louis, King Louis IX of France, and serves as the seat of the Archdiocese of New Orleans. A 1906 church census recorded services in both English and French, and the sacramental register switched from French to English in 1910. Several archbishops are buried here, including Mgr Blanc (1835-1860), Mgr Perché (1870-1883) and Mgr Janssens (1888-1897).

Entry is possible during most daytime hours except during services, and visitors should remain quiet and respect any liturgical activities taking place. Tours offer further insight into the construction details and artworks visible inside the building.

The 1819 central tower, designed by Benjamin Henry Latrobe, held a bell embossed with the name "Victoire" for the 1815 Battle of New Orleans. When the tower collapsed during the 1850 reconstruction, that bell was saved and reused in the present building, where it remains.