Holy Trinity is the town parish church, on South Street near the Town Hall. The current building dates from a major Victorian rebuild of 1907–9 but incorporates the medieval west tower and several 15th-century features. John Knox preached his first public sermon here in June 1559 — the sermon that triggered the cathedral's stripping by the Reformed mob.
The interior contains a richly carved marble monument to Archbishop James Sharp, murdered on Magus Muir outside the town in 1679. The east window by Douglas Strachan is among the finest pieces of early-20th-century stained glass in Scotland. The church is usually open during the day; entry is free.