Princess Eugénie of Greece and Denmark (Greek: ??????p?ssa ???e??a t?? ????da? ?a? ?a??a?) (10 February 1910 – 13 February 1989) was the youngest child and only daughter of Prince George of Greece and Denmark and his wife, Princess Marie Bonaparte, daughter of Marie-Félix Blanc and Prince Roland Bonaparte, a great-nephew of Napoleon I.
Her father was the second son of George I of Greece and Olga Constantinovna of Russia.As a cousin of the bridegroom, she was a leading guest at the 1947 wedding of Princess Elizabeth and Philip, Duke of Edinburgh.She authored Le Tsarevitch, Enfant Martyr, a biography of Aleksey Nikolaevich, Tsarevich of Russia, written in French, which was published in 1990.