Princess Tatiana Maria Renata Eugenia Elisabeth Margarete Radziwiłł (born 28 August 1939) is a French-Polish aristocrat, bacteriologist, and nurse.

[1] She is a member of the House of Radziwill, a Polish-Lithuanian noble family, and is the granddaughter of Prince Hieronim Mikołaj Radziwiłł and Archduchess Renata of Austria.

Radziwiłł and her parents fled their home in 1940 after the Fall of France, taking refuge in Saint-Tropez before going in to exile in South Africa, then part of the British Empire.

[1] Throughout her childhood, Radziwiłł became close friend with her second cousin, Princess Sophia of Greece and Denmark (the future Queen of Spain).

[2] She remained close to the Greek royal family, serving as a bridesmaid for her cousin, Princess Sophia, when she married the future King of Spain in 1962.

She is also a Dame Grand Cross of the Order of Saints Olga and Sophia and was awarded the Commemorative Badge of the Centenary of the Kingdom of Greece.

Radziwiłł is portrayed by Paloma Bloyd in Antonio Hernández's 2011 Spanish television film directed Sofía.

In his 2013 book, La récréation, Frédéric Mitterrand writes about attending an exhibition on Princess Marie Bonaparte with Radziwiłł.