Henri Leclercq (4 December 1869 – 23 March 1945) was a French Catholic priest, theologian, and church historian who spent most of his adult life in the United Kingdom.

Born in Tournai, Belgium, Leclercq attended the Catholic school there, but dropped out at the age of 17 when his mother moved him and his older sister to Paris; his father had died in 1874.

[2] With Prior Fernand Cabrol and other monks he was sent, in 1896, to Farnborough, in the south of England, where former empress Eugénie de Montijo had founded Saint Michael's Abbey.

To complete these volumes he spent more and more time in London, in the reading room of the British Museum.

This in turn led to an appointment in the Italian hospital of Queen's Square; later he moved to the house of the Congregation of Our Lady of Sion in Bayswater, and was canonically released from the Benedictines to join the clergy of the Roman Catholic Diocese of Westminster.