St Mary's Cathedral, Limerick, Anglican cathedral in Limerick, Ireland.

St Mary's Cathedral is a Church of Ireland cathedral on King's Island in Limerick, founded in 1168 and the oldest building in the city still in use. Its 14th-century tower rises 36.58 metres and holds a peal of eight bells. The great west door is said to have been the entrance of Domnall Mór Ua Briain's palace, and the interior keeps the only complete set of misericords in Ireland.

The cathedral was founded in 1168 by King Domhnall Mhor O'Brien on the site of his royal palace, which stood over a former Viking gathering place. The building was rebuilt and added to many times over the following centuries, though its medieval core has remained.

The medieval wooden carvings tucked under the choir seats are called misericords and show animals, saints, and everyday scenes from past centuries. These small carvings are among the rarest of their kind still surviving in Ireland.

The cathedral is open to visitors on weekdays, though access can vary depending on services being held at the time. Arriving in the early afternoon generally gives a better chance of exploring the interior without interruption.

The stones around the cathedral's west door carry scratch marks left by defenders sharpening their weapons during historical sieges of Limerick. These marks are easy to miss but are right there on the stonework, connecting the building directly to the city's past conflicts.