Princess Augusta of Hesse-Cassel, later the Her Royal Highness the Duchess of Cambridge, (7 July 1797 – 6 April 1889) was the consort of Prince Adolphus, 1st Duke of Cambridge, the tenth born child and seventh son of King George III of the United Kingdom and Queen Charlotte. The longest-lived daughter-in-law of George III, she was the maternal grandmother of Queen Mary, the consort of King George V of the United Kingdom.

Her Highness Princess Augusta Wilhelmina Louisa, the third daughter of Friedrich III, Landgrave of Hesse-Cassel and his wife Caroline Polyxena, daughter of Prince Karl Willem of Nassau-Usingen, was born at Rumpenheim Castle, Cassel, Germany. Her father, Landrave Friedrich III, was the son of Princess Mary (22 February 1723-14 January 1772), the third daughter of King George II of Great Britain. In 1803, he assumed the title of Elector of Hesse-Cassel.

On 7 May at Cassel and then again on 1 June 1818, Princess Augusta married her second cousin, the Duke of Cambridge, when she was 21 and he was 43. The Duke and Duchess of Cambridge had three children:

• Prince George, 2nd Duke of Cambridge (26 March 1819-17 March 1904)
• Princess Augusta of Cambridge (19 July 1822-4 December 1916), m. Friedrich Wilhelm, Grand Duke of Mecklenberg-Strelitz (1819-1904)
• Princess Mary Adelaide of Cambridge (27 November 1833-27 October 1897) m. Prince Francis of Teck, later 1st Duke of Teck.

From 1818 until the ascension of Queen Victoria and the separation of the British and Hanoverian crowns in 1837, the Duchess of Cambridge lived in Hanover, where the Duke served as viceroy on behalf of his brothers, King George IV and King William IV. The Duke and Duchess of Cambridge returned to Great Britain, where they lived at Cambridge Cottage, Kew, and later at St. James' Palace. The Duchess of Cambridge survived her husband by thirty-nine years, dying at the age of almost ninety-two.