Catherine Pegge, born about 1635, was a long term mistress of Charles II. She had two children by him, Charles FitzCharles, 1st Earl of Plymouth and Catherine FitzCharles.
Catherine was the daughter of Thomas Pegge of Yeldersley, Ashbourne, Derbyshire, and wife Catherine Kniveton, daughter of Sir Gilbert Kniveton, Baronet, and wife. Thomas and his family were exiled to Bruges during the English Civil War following his capture serving under the Royalist Colonel General Henry Hastings, 1st Baron Loughborough. It was in Bruges that Catherine's liaison with Charles II began, resulting in the birth of her son in 1657.
There are allegedly two portraits of Catherine Pegge by Sir Peter Lely, the whereabouts of which are unknown.
The Yeldersley branch descended from Thomas Pegge. She was said to have great beauty.
Her son died in 1680. She went on to marry before 1667 Sir Edward Greene of Sampford in Essex, Baronet on 26 July 1660, who died at Flanders in 1676 and was interred at Sampford, Essex, but they had no further children besides one Justinia Greene (1667–1717), one of the English Ladies of the Pontoise.