Martin Compston (born 8 May 1984) is a Scottish actor and former professional footballer. He played Anti-Corruption Unit Detective Inspector Steve Arnott in the BBC drama Line of Duty, Liam in Ken Loach's Sweet Sixteen, Paul Ferris in The Wee Man, Ewan Brodie in Monarch of the Glen and Dan Docherty in The Nest.

Early life and football career
Born to a Catholic family, Compston, the younger of two sons, was brought up in Greenock, Scotland, and attended St Columba's High School in neighbouring Gourock.

A promising footballer, he was a youth player with Aberdeen as a teenager, and after leaving school signed for his local professional club Greenock Morton. Compston made two first-team appearances in the 2001–02 season, in which the team was relegated to the Third Division. In both matches he appeared as a substitute and Morton lost 4–0, to Alloa Athletic and Queen of the South. After leaving Morton, he briefly played in junior football for Greenock Juniors.