William Cunningham, 9th Earl of Glencairn (1610–1664), was a Scottish nobleman, Lord Chancellor of Scotland, and a cavalier. He was also the chief of Clan Cunningham.

Clan Cunningham is a Scottish clan. The traditional origins of the clan are placed in the 12th century. However, the first contemporary record of the clan chiefs is in the thirteenth century. The chiefs of the Clan Cunningham supported Robert the Bruce during the Wars of Scottish Independence. In the 15th and 16th centuries, the Clan Cunningham feuded with the Clan Montgomery. Historically, the chief of Clan Cunningham held the title of Earl of Glencairn. However, in modern times the chief of the clan is Cunningham of Corsehill. On 18 December 2013, Sir John Christopher Foggo Montgomery Cunninghame, Baronet of Corsehill, was recognized by Lord Lyon as Clan Chief after the chiefship had been vacant for over 200 years.