Anna Constantia von Brockdorff (17 October 1680 – 31 March 1765), later the Countess of Cosel, was a German lady-in-waiting and noblewoman, and mistress of Augustus the Strong, King of Poland and Elector of Saxony, in 1706–1713. Eventually he turned against her and exiled her to Saxony, where she died after 49 years of internal exile.