Princess Dorothea of Denmark (29 June 1546 – 6 January 1617) was the Duchess of Brunswick-Lüneburg from 1561 until 1592 as the consort of Duke William the Younger.

Born in Kolding, Dorothea was the youngest child of Christian III of Denmark-Norway and Dorothea of Saxe-Lauenburg.

She married William, Duke of Brunswick-Lüneburg on 12 October 1561.

When her husband died in 1592, she became regent for her under age son George.

She had a deep mistrust of the councillors because of their ill management of her husband's estates during his insanity.