Athina Maria "Tina" Onassis Niarchos (née Livanos; Greek: Αθηνά (Τίνα) Λιβανού, pronounced [aθiˈna ˈtina livaˈnu]; 19 March 1929 – 10 October 1974) was an English-born Greek-French socialite and shipping heiress, the second daughter of the Greek shipping magnate Stavros Livanos and Arietta Zafirakis.

She was known best as the first wife of Aristotle Onassis, but she later married her older sister Eugenia's widower, Stavros Niarchos.

Her husbands were: After her divorce from Aristotle Onassis, she resumed using her maiden name, Livanos, until her marriage to Spencer-Churchill.

[2] Athina Niarchos died on 10 October 1974 in the Hôtel de Chanaleilles, the Parisian mansion that she shared with her husband.

Her death was officially ruled by pathologists as having resulted from an acute edema of the lung, but has also been attributed to her suffering a drug overdose.