Sergio Ayala López (born 19 March 1993) is a Spanish footballer who plays for Belgian club Sint-Truidense V.V. as a defender.
Born at Sant Feliu de Llobregat in Barcelona, Ayala joined FC Barcelona's youth academy at the age of 7 in 2000. After being an undisputed starter of the Juvenil A during the 2011–12 season, he was promoted to Barcelona B on 18 June 2012, and signed a contract which would keep him in the club till 2015.
On 21 August 2012, Ayala joined Alavés on loan for the 2012–13 season. On 21 August 2013, he moved to Valencia Mestalla on loan. After having featured 33 times for the side, he signed permanently with the club on 14 July 2014. On 20 September 2015, he scored his first goal for the club in a 2–3 defeat against Cornella.
On 25 July 2017, Ayala moved abroad for the first time, signing for Belgian club Sint-Truidense V.V. on a one-year contract.