Thierry Roussel (born February 16, 1953) was the fourth husband of Christina Onassis, and the only man with whom she had a child, daughter Athina Onassis Roussel. Roussel is best known as the controversial former co-trustee of his eldest child's famous fortune and for having been involved in a number of legal entanglements with the four Greek trustees of that fortune. These disputes were mostly ended (or quieted) in 1999 by the court-ordered transfer of the administration of Athina's trust to a private auditing firm.