Spyros Stavros "Spiros" Niarchos (Greek: Σπύρος Νιάρχος; born 1955) is the second son of the Greek shipping magnate Stavros Niarchos and Eugenia Livanos. He is a grandson of another Greek shipping giant, his mother's father, Stavros G. Livanos.
In 1955 Vickers Armstrongs Shipbuilders Ltd launched for Stavros Niarchos what was then the World's largest supertanker. The 30,708 GRT ship was named SS Spyros Niarchos after his new son.
In 1987, while skiing in Switzerland, he met 19-year-old Daphne Guinness (artist, socialite and an heiress of the Guinness family) and they soon married. The marriage ended in divorce, with Guinness receiving a GBP 20 million settlement in 1999.
The couple has three children:Nicolas Stavros Niarchos (born 1989)Alexis "Lex" Spyros Niarchos (born 1991)Ines Sophia Niarchos (born 1995)
In January 1999, Niarchos was a witness at the wedding of his best friend, Ernst August V, Prince of Hanover. He is the godfather of Crown Prince Pavlos' youngest son, Aristides-Stavros. With his brother, Philip, Niarchos is Co-President and Member of the board of directors at the Stavros Niarchos Foundation.