Roberto Fabián Ayala (born April 14, 1973 in Paraná) is an Argentinian soccer player, who currently plays for the Spanish team Valencia.

On the club level, Ayala has played for Ferrocarril Oeste (1991-94), River Plate (1994-95), Napoli (1995-98), and Milan (1998-2000). Ayala played for Argentina in the 1998 World Cup and was a non-playing squad member in the 2002 edition. He was then an over-age player as Argentina won the gold medal at the 2004 Summer Olympics.

He prefers to be known as Fabián Ayala.