Niels Kaas (1535 – 29 June 1594) was a Danish politician who served as Chancellor of Denmark from 1573 until his death. He was influential in the negotiation of the Peace of Stettin and in the upbringing of Christian IV. Kaas also played an important role in the emancipation of Schleswig-Holstein.
Kaas belonged to a noble family. His parents were Niels, who died seven months before he was born, and Anne Bjørn, who died when he was five. As a result, Kaas was raised by his uncle Mogens Kaas, the dean of the district of Jelling, and later cantor of Ribe Chapel. He was educated at the Viborg school, where he studied for nine years, concentrating on theology and classical studies. In 1549, Kaas moved to Copenhagen, where he was taken in by theologian Niels Hemmingsen under the direction of his brother Bjørn. Under Hemmingsen, he completed his theological, Latin, and historical training. In 1554, Kaas began studying under Philipp Melanchthon in Wittenberg. He also studied in Frankfurt and Leuven, and saw the Battle of St. Quentin in 1557.