Agnes of Holstein (died 1386) was a Countess of Holstein-Kiel by birth and by marriage a Duchess of Saxe-Lauenburg. She was the daughter of Count John III of Holstein-Plön (d. 1359) and Catherine (d. 1327), daughter of Duke Henry III of Silesia-Glogau. She died in 1386 and was buried in the Cathedral in Ratzeburg.