Enzo Jeremías Fernández (এনজো জেরেমিয়াস ফার্নান্দেজ) is an Argentine professional footballer who plays as a midfielder for Premier League club Chelsea and the Argentina national team. Primarily a central midfielder, he is also capable of playing as a defensive or attacking midfielder.

On 24 July 2019, Fernández was selected by the Argentina U18s manager Esteban Solari to represent his nation at the 2019 COTIF Tournament in Spain. On 3 November 2021, he was called up by Argentina national team manager Lionel Scaloni for two 2022 FIFA World Cup qualifiers against Brazil and Uruguay. He made his senior team debut on 24 September 2022, by coming on as a 64th-minute substitute for Leandro Paredes in a 3–0 win against Honduras. On 11 November, he was named in Argentina's 26-man squad for the 2022 FIFA World Cup. After coming on for Guido Rodríguez in the 57th minute, on 26 November, Fernández scored his first international goal, closing Argentina's 2–0 group stage win against Mexico. In doing so, he became the second youngest player ever (only behind Lionel Messi) to score a World Cup goal for Argentina at 21 years, ten months and thirteen days old. On 3 December, he achieved a rather not so famous record, becoming the youngest own goal scorer in the history of Argentina in the FIFA World Cup, in the round of sixteen match against Australia, when his attempt to block Craig Goodwin's shot deflected into his team's net as Argentina beat Australia 2–1. After defeating Croatia 3–0 in the semi-final, Fernández played in the final against France, where Argentina won the World Cup by a score of 4–2 on penalties after a 3–3 draw. He was named the best young player of the tournament.

A versatile midfielder, Fernández usually plays as a deep-lying playmaker, responsible for breaking up play, dictating the tempo, and recycling possession, but he is also a capable attacking-midfielder. Although he prefers operating centrally, he can be seen occupying the left half-space assisted by a defensive midfield partner, like his former Benfica team-mate, Florentino Luís.

Fernández is named after three-time Copa América winner and former River Plate player Enzo Francescoli, due to his father Raúl's fascination with the Uruguayan. In an interview, he said that his favorite player is Lionel Messi.

Fernández was married to fellow Argentine Valentina Cervantes, with whom he has a daughter, born on 4 March 2020. On 26 October 2023, their son was born.

On 31 October 2024, Cervantes announced on her Instagram story that she and Fernandez were separating, writing (translated from Spanish) "Enzo and I have decided to take some distance from each other today. But we will always be family, and we will support each other in everything, because there are two children involved who need a lot of love from us. I know the person Enzo is, what an excellent father he is, and what heart he has. And that is enough for me. Please don't try to create conflicts where there are none."