The title Earl of Kellie or Kelly is a title in the Peerage of Scotland, created in 1619 for Sir Thomas Erskine, who was Captain of the Guard and Groom of the Stool for James VI. It is named after Barony of Kellie in Fife, Scotland. Since 1875, it has been held jointly with the Earldom of Mar.

There are currently two earldoms of Mar in the Peerage of Scotland, and the title has been created seven times. The first creation of the earldom is currently held by Margaret of Mar, 31st Countess of Mar, who is also clan chief of Clan Mar. The seventh creation is currently held by James Erskine, 14th Earl of Mar and 16th Earl of Kellie, who is also clan chief of Clan Erskine.