Princess Marina, Duchess of Kent (13 December 1906 - 27 August 1968), the former Princess Marina of Greece and Denmark, was the last foreign-born princess to date to marry into the British Royal Family.

Princess Marina was born in Athens, the third daughter of Prince Nicholas of Greece and Denmark and his wife, Grand Duchess Helen Vladimirovna of Russia. Prince Nicholas was the second son of King George I of the Hellenes, the younger brother of Queen Alexandra, the consort of King Edward VII of the United Kingdom. One of her paternal uncles was Prince Andrew of Greece and Denmark, the father of Prince Philip, Duke of Edinburgh. Her mother was a granddaughter of Tsar Alexander II of Russia. She was the youngest sister of Princess Paul of Yugoslavia, born Princess Olga of Greece and Denmark and of Countess Carl Theodor zu Toerring-Jettenbach, born Princess Elizabeth of Greece and Denmark.

Brought up in genteel poverty, she married Prince George, Duke of Kent, the bisexual fourth son of King George V of the United Kingdom of Great Britain and Northern Ireland, on 29 November 1934 at Westminster Abbey, London. Whereas his sister, Mary, Princess Royal, and two of his elder brothers, the Prince Albert, Duke of York (later King George VI) and Prince Henry, Duke of Gloucester married offspring of the English and Scottish aristocracy, the Duke of Kent reverted to the pre-World War I practice among British princes of selecting a bride from a Continental royal family.

The Duke and Duchess of Kent had three children: the current Duke of Kent, Princess Alexandra, the Honourable Lady Ogilvy, and Prince Michael of Kent. Her husband died on 25 August 1942 in an aeroplane crash at Eagles Rock, near Dunbeath, Caithness, Scotland while on active service with the Royal Air Force. After her husband's death, the Duchess of Kent continued to be active member of the British Royal Family, carrying out a wide-range of royal and official engagements. She was the longtime president of the Wimbledon All England Lawn Tennis and Croquet Club.

Just before the current Duke of Kent's wedding in June 1961 to Katherine Wosley, she announced that she wished to be known as "HRH Princess Marina, Duchess of Kent" instead of "HRH The Dowager Duchess of Kent." Upon her marriage in 1934, she became "HRH The Princess George, Duchess of Kent, Countess of St. Andrews, and Baroness Downpatrick." However, she remained a princess of Greece and Denmark in her own right. Following her elder son's wedding, she simply reverted to her own title.

She died of a brain tumor at Kensington Palace on 27 August 1968.

Princess Marina reputedly had a sharp tongue and reportedly once referred to her sisters-in-law, Princess Alice, Duchess of Gloucester, and Queen Elizabeth the Queen Mother as "common Scotch girls."