 Simpson was awarded a testimonial match by Aberdeen in 2012, which was played against a Manchester United XI on 14 August 2012.Having played in the Scotland Under-17 and Under-18 sides and captained the Under-21 team, Simpson made his full Scotland debut in the penultimate British Home Championship against Northern Ireland at Hampden, which ended in a goalless draw.In the 1983–84 season he appeared in two friendlies, beating Uruguay 2–0 and losing 2–0 to France.