The Queen's Chapel is a chapel in central London, England, that was designed by Inigo Jones and built between 1623 and 1625 as an external adjunct to St. James's Palace for Roman Catholic queen Henrietta Maria. It is one of the facilities of the British monarch's personal religious establishment, the Chapel Royal, and should not be confused with the 1540 building known as the Chapel Royal within the palace and just across Marlborough road.
It was built as a Roman Catholic chapel at a time when the construction of Catholic churches was prohibited in England, and was used by Charles I's Catholic queen Henrietta Maria. From the 1690s it was used by Continental Protestant courtiers. It was built as an integral part of St James's Palace, but when the adjacent private apartments burned down in 1809 they were not replaced and in 1856-57 Marlborough Road was built between the palace and the Queen's Chapel. The result is that physically the chapel now appears to be more part of the Marlborough House complex than of St James's Palace. It became a Chapel Royal again in 1938.