is a professional football manager and former player who is currently the head coach of Scottish Premiership club Rangers. Born in England, he represented Scotland at international level.

A former defender, Martin began his playing career at Brighton & Hove Albion's youth academy. He established himself at Wycombe Wanderers in 2004, before moving to Peterborough United in 2008. Martin joined Norwich City in 2010 and made 309 appearances for the club. He then had brief spells with Rangers, Walsall and Milton Keynes Dons. During his playing career, Martin won five promotions (including two promotions to the Premier League) and was named in the 2014–15 Championship Team of the Year by the Professional Footballers' Association.

Although born in Brighton, England, Martin played in 29 internationals for Scotland. He moved into management in 2019 with Milton Keynes Dons and became head coach of Swansea City in 2021. Two years later, he was appointed manager of Southampton. He guided them to promotion to the Premier League by winning the playoffs, but was sacked in December 2024. Martin was made head coach of Rangers in June 2025.