Agnes Keith, Countess of Moray was a Scottish noblewoman. She was the wife of James Stewart, 1st Earl of Moray, regent of Scotland and the illegitimate half-brother of Mary, Queen of Scots, making her a sister-in-law of the Scottish queen. As the wife of the regent, Agnes was the most powerful woman in Scotland from 1567 until her husband's assassination in 1570.

James Stewart, 1st Earl of Moray was a member of the House of Stewart as the illegitimate son of King James V of Scotland. At times a supporter of his half-sister Mary, Queen of Scots, he was the regent of Scotland for his half-nephew, the infant King James VI, from 1567 until his assassination in 1570. He was the first head of government to be assassinated with a firearm.