Kaja Kallas (born June 18, 1977) is an Estonian politician and diplomat. She was the first female prime minister of Estonia, a role she held from 2021 until 2024, when she resigned in advance of her appointment as High Representative of the European Union for Foreign Affairs and Security Policy. Since 2024, she has served in that role as well as Vice-President of the European Commission in the second von der Leyen Commission.