William de Moravia (also known as William Sutherland) (died 1370) was the 5th Earl of Sutherland and chief of Clan Sutherland. William, 5th Earl of Sutherland was a loyal supporter of David II of Scotland in the wars against England. William succeeded in taking Roxburgh Castle back from the English.
He married Margaret Bruce in 1345, a daughter of King Robert I of Scotland (Robert the Bruce) and his second wife Elizabeth de Burgh. With Margaret Bruce, William, Earl of Sutherland only had one son:
- John of Sutherland, who was to succeed to the throne of Scotland by royal descent through his mother Margaret Bruce, but died of plague in London and so Robert II of Scotland, nephew of David II of Scotland became the next king.
William, Earl of Sutherland married his second wife, Joanna daughter of Sir John Menteith in 1346.
In 1360, William, 5th Earl of Sutherland granted to his brother Nicholas Sutherland, younger son of the 4th Earl, the barony of Thoroboll. From this Nicholas Sutherland descended the Sutherland Lairds of Duffus.
William de Moravia, 5th Earl of Sutherland had issue:
- Robert de Moravia, 6th Earl of Sutherland (Robert Sutherland).
- Kenneth Sutherland, 1st Laird of the Sutherland of Forse family.
- John Beg Sutherland.