Iñigo Martínez Berridi is a Spanish professional footballer who plays as a centre-back for La Liga club Barcelona and the Spain national team.

He spent most of his professional career with Real Sociedad, playing 238 matches (17 goals scored) in all competitions after making his debut at the age of 20. In January 2018, he signed with Athletic Bilbao, with whom he won the 2020–21 Supercopa de España as well as reaching two Copa del Rey finals.

Martínez made his debut for the Spain under-21 team in 2011. In the following year, he was picked by manager Luis Milla for his squad that appeared in the 2012 Summer Olympics in London. In the first game against Japan he was sent off late into the first half for bringing down Kensuke Nagai, thus denying a clear goalscoring opportunity, in an eventual 1–0 loss.

Martínez made his first appearance with the full side on 14 August 2013, coming on as a second-half substitute for Sergio Ramos in a 2–0 friendly win over Ecuador. Between September 2018 and March 2021 he received eleven caps, including seven starting appearances; however, he was not included in Luis Enrique's 24-man squad for the UEFA Euro 2020 tournament (delayed for a year by the COVID-19 pandemic in Europe) when it was announced on 24 May, with the player stating that he was not totally happy with his physical situation having missed a number of club matches during the season and an agreement had been made between him, the national body and Athletic that he would not take part.

Martínez is likened to compatriot Carles Puyol and is known for his heading ability which made him an aerial threat on set pieces, despite his modest stature of 1.82 m (5 ft 11+1⁄2 in). He is also known for his tackling and leadership qualities and ability to read the game, as well as competence with the ball at his feet.

Martínez is considered a specialist in the offside trap.