Ratass Church, Church ruin in Tralee, County Kerry, Ireland

Ratass Church is a sandstone church ruin in Tralee featuring remaining walls and a west gable end. The small structure sits within an old cemetery where a purple sandstone ogham stone with ancient Irish inscriptions can be found.

A ringfort or embanked enclosure, Rath Mhaighe Teas ("fort of the southern plain"), stood here before a sandstone church was built in the 10th century. The west gable and part of the nave walls survive from that construction. The church served as the episcopal seat of a Kerry diocese from 1111 to 1117, when the seat was moved to Ardfert; the rest of the building is later work.

The name Ráth Teas comes from Rath Mhaighe Teas, "fort of the southern plain", recalling the ringfort or embanked enclosure built here before the church. The ogham stone, read as "[A]NM SILLANN MAQ VATTILLOGG" ("name of Sílán son of Fáithloga"), records a personal name in Primitive Irish and is kept in the graveyard on Quill Street.

The church and graveyard stand on Quill Street in Tralee's eastern suburbs, at 52°16′01″N, 9°40′55″W. The ogham stone was found in 1975 built almost flush against the wall of a 19th-century burial vault, so look low along the vault wall rather than at the church itself.

The ogham stone predates the church by centuries: its Primitive Irish wording, "[A]NM SILLANN MAQ VATTILLOGG" (name of Sílán son of Fáithloga), points to about AD 550–600. It was found in 1975 during a cleanup, almost flush with the wall of a 19th-century burial vault built against it.