Roger de Leybourne or Roger Leyburn was a Lord Warden of the Cinque Ports and Sheriff of Kent, and was known as a general administrator. He is thought to have served twice in the post of Lord Warden, once from 1264, and from 1271.

In 1271 Roger de Leybourne embarked on a crusade with Prince Edward, returning a seasoned warrior. When Edward was made a prisoner of the barons at Wallingford, Leybourne at some length effected the princes escape. When the prince became King Edward I he visited the castle at Leyborne to stay with Roger de Leybourne's son, who was the first Englishman to be called an admiral.

The Norman Leybourne Castle, long time but ruins, has been occupied by the estate of Leybourne Grange, a private manor converted into an hospital (also now long since closed). It is situated beside the parish church, also partially Norman, and which was rebuilt in the 14th century.

Roger de Leyburn was the father of William de Leyburn, the first Baron, who owned Ledes Castle, near Maidstone, in Kent. He left Leybourne Castle and took up residence at Preston at a "Grand Residence and large possessions" previously owned by his father-in-law, Sir Henry de Sandwich.

During the Second Barons' War de Leybourne fought at the Battle of Evesham as a royalist, against the barons led by Simon de Montfort:

"On the battlefield in the bloody slaughter Roger de Leybourne noticed the wounded and confused figure of the king and dragged him, bleeding from a face wound, to safety".

Lord Warden of Cinque Ports.

Henry de Sandwich had been Lord Warden of the Cinque Ports previously to de Leyburn, but the records of the administration during this period for the office is uncertain. It is understood that Walter de Burgsted was Lord Warden in 1262, and followed Henry de Sandwich, who was succeeded by John de Haia before Sir Roger de Leybourne thought to have served twice once during 1264 only two years later. Henry de Montfort was also Lord Warden in 1264.