St Hilary's Chapel (also St Hilary's Church) is a former church in Denbigh, Denbighshire, north Wales, of which only the tower remains.
The town's garrison church, it lay to the north Denbigh Castle.
It dates to c. 1290, when the borough town was built by Henry de Lacy, Earl of Lincoln; the earliest mention of it is in 1334.
On 28 September 1645, during the English Civil War, a service at the church was attended by Charles I, the Archbishop of York, Lord Keeper Williams and numerous other important officials.
In 1923 the church was largely demolished, leaving just the tower of roughly 14 metres (46 ft).