Alexander Socrates Onassis (Greek: Αλέξανδρος Ωνάσης; April 30, 1948 – January 23, 1973) was an American-born Greek businessman. He was the son of the Greek shipping magnate Aristotle Onassis and his first wife Tina Livanos. He and his sister Christina Onassis were upset by his father's marriage to Jacqueline Kennedy, and he was credited with attempting to improve the relationship between his father and Stavros Niarchos.