, also known as Dibu, is an Argentine professional footballer who plays as a goalkeeper for Premier League club Aston Villa and the Argentina national team. Known as a specialist in saving penalty kicks, Martínez is widely regarded as one of the best goalkeepers in the world.

Martínez trained at Independiente's youth ranks before moving to Premier League club Arsenal in 2010. At Arsenal, he initially served as understudy, being loaned to various clubs, before breaking into the starting line-up in 2019, featuring in the Premier League and helping the club win a FA Cup and FA Community Shield. In September 2020, Martínez moved to fellow Premier League club Aston Villa in a transfer worth £20 million. In his first season at the club, he kept a club-record fifteen clean sheets in the Premier League.

Martínez represented Argentina in junior international matches from 2009 to 2011, playing on under-17 and under-20 levels. He earned his first senior cap for the Argentina in 2021 and won the 2021 Copa América with the team, receiving the Golden Glove award. Martínez went on to win the 2022 FIFA World Cup with Argentina, again being voted best goalkeeper of the tournament, and the 2024 Copa América, where he was awarded the Golden Glove a third time. He was also named The Best FIFA Goalkeeper a record two times in 2022 and 2024, and received the Yashin Trophy, also a record two times, in 2023 and 2024.