Agnes Keith, Countess of Moray

Agnes Keith, Countess of Moray (c. 1540 – 16 July 1588) was a Scottish noblewoman having been the eldest daughter of William Keith, 4th Earl Marischal and Margaret Keith. 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.

She was married secondly to Sir Colin Campbell, heir presumptive to the earldom of Argyll. When he succeeded his brother as the 6th earl in 1573, Agnes was henceforth styled Countess of Argyll. During her second marriage, Agnes became embroiled in a litigation over Queen Mary's jewels which had earlier fallen into her keeping. It was her refusal to hand the jewels over to the Scottish Government that sparked a feud between the Earl of Argyll and the Regent Morton.