Paul de Rapin (25 March 1661 – 25 April 1725), sieur of Thoyras (and therefore styled Thoyras de Rapin), was a French historian writing under English patronage.

The son of Jacques de Rapin, an avocat at Castres (Tarn), he was educated at the Protestant Academy of Saumur, and in 1679 became an advocate, but soon afterwards joined the army. The revocation of the Edict of Nantes in 1685, and the death of his father led him to move to England; but, unable to find work there, he went on to the Netherlands where he enlisted in a company of French volunteers at Utrecht, commanded by his cousin, Daniel de Rapin.

He accompanied William III to England in 1688, and during the Williamite war in Ireland he took part in the Siege of Carrickfergus and the Battle of the Boyne, and was wounded at the Siege of Limerick (1690). Soon afterwards he was promoted to captain; but in 1693 he resigned in order to become tutor to the Earl of Portland's son. After travelling with the boy, he settled with his family (he married Marie-Anne Testart in 1699) in Holland, first at the Hague, then, to save money, at Wesel, in 1707.