Who was Frank Sinatra's fourth and final wife?

Frank Sinatra's fourth and final wife was Barbara Marx. They married on July 11, 1976, and remained together until Sinatra's death in 1998.

Born Barbara Ann Blakeley, she had previously been married to Robert Oliver and comedian Zeppo Marx, one of the Marx Brothers. That history explains why she is often identified in older sources as Barbara Marx, while later references commonly call her Barbara Sinatra.

The marriage was Sinatra's fourth, following Nancy Barbato, Ava Gardner, and Mia Farrow. It was also his longest-lasting marriage. Barbara converted to Catholicism before the wedding and stayed closely involved in Sinatra's personal and business affairs during his final decades.

A common mix-up is to identify Nancy Barbato as his final wife because she was the mother of his three children and remained an important figure in his life. Nancy was Sinatra's first wife; Barbara Marx was the woman who was married to him when he died.