Lisandro Martínez (born 18 January 1998) is an Argentine professional footballer who plays primarily as a centre-back for Premier League club Manchester United and the Argentina national team. Martínez began his career at Newell's Old Boys before joining Defensa y Justicia in 2017, initially on loan. In 2019, he signed for Ajax and has since won two Eredivisie titles and one KNVB Cup. He won the Ajax Player of the Year award in the 2021–22 season. Martínez represented Argentina at under-20 and under-23 levels, before making his senior international debut in March 2019. He was a member of the squads that won the 2021 Copa América and the 2022 Finalissima.