Lombez Cathedral (Cathédrale Sainte-Marie de Lombez) is a Roman Catholic cathedral, and a national monument of France, in Lombez.

It was the seat of the former Diocese of Lombez, suppressed by the Concordat of 1801 and divided between the Diocese of Bayonne and the Archdiocese of Toulouse.

This is a 14th century brick church with an ornate pink-and-white five-tiered octagonal bell tower constructed c. 1346. A plaque to the right of the plain west entrance records the visit of the Italian poet Petrarch in 1330, arranged by the bishop, Jacques Colonna (1328-41), also of Italian extraction, who made Petrarch an honorary canon in 1335. The typical blank west façade of meridional Gothic is relieved only by a small roundel and the Flamboyant entrance in stone. The severe exterior is characteristic of the Midi Toulousain region with tall buttresses around the chevet.

Below the tower in the interior is a remarkable 12th century baptistry, which was part of an earlier church. The lead baptismal font is made of two pieces, the lower part decorated with religious figures in medallions in the style of the 13th century, and the upper part with a frieze of secular scenes of antique design. The stopper in the base suggests it was used for total immersion which was practised until the 9th century.