The Acropolium, also known as Saint Louis Cathedral is a Roman Catholic church located in Carthage, Tunisia.

The cathedral sits on the peak of Byrsa Hill, near the ruins of the ancient Punic and then Roman city. It was built atop the ruins of an old temple dedicated to Eshmun, the Punic god of healing. The edifice can still be accessed from the basement.

Since 1993, the cathedral has been known as the "Acropolium". It is no longer used for worship, but instead hosts public events or concerts of Tunisian music and classical music. Currently, the only Roman Catholic cathedral operating in Tunisia is the Cathedral of St. Vincent de Paul in Tunis.

Late 19th century French architecture tended to feature composite styles (as in the case of the Basilica of the Sacré Cœur in Paris, built in the Romanesque-Byzantine architectural tradition in the same era). The building, constructed according to the plans of the abbot Pougnet, has a Byzantine-Moorish style, and is in the shape of a Latin cross of 65 meters by 30. The façade is framed by two square towers, the crossing lies beneath a large cupola surrounded by eight little steeples, and there is a smaller cupola above the apse. The church contains a nave and two aisles separated by arches passing above. Its ceiling is adorned with beams that have sculpted, painted and gilt arabesques on them. The stained glass also features arabesques. The great bell weighs six tons and there is a four-bell carillon as well.