Nils Middelboe was a Danish amateur track and field athlete and football player as well as a football referee and leader. He represented the Denmark national football team at the 1908, 1912 and 1920 Summer Olympics, winning silver medals in 1908 and 1912. He was the first ever goalscorer for the Denmark national football team, when he scored in Denmark's debut game at the 1908 Summer Olympics. In 1913, he moved abroad to play for English club Chelsea, and became the first foreign player to ever represent the club.

Football at the 1912 Summer Olympics was one of the 102 events at the 1912 Summer Olympics in Stockholm, Sweden. It was the fourth time that football was on the Olympic schedule.