This was the 15th (medal) appearance of the men's singles tennis event. The event has been held at every Summer Olympics where tennis has been on the program: from 1896 to 1924 and then from 1988 to the current program. Demonstration events were held in 1968 and 1984. The number one seed was
Novak Djokovic of Serbia, making his third Olympic appearance after reaching the semifinals in 2008 (bronze medal) and 2012 (fourth place), Djokovic had been the winner of the first two majors of the year, the Australian and French Open, and was also the reigning U.S. Open champion. The returning Olympic champion and number two seed was
Andy Murray of Great Britain, coming off winning his second Wimbledon title, and his first Davis Cup the previous autumn; he had also been runner-up to Djokovic in Melbourne and Paris. Spain's
Rafael Nadal, the 2008 gold medalist who was unable to compete in 2012 due to injury, was the third seed. Sidelined with injury this time was
Roger Federer of Switzerland (who, like Djokovic, needed only an Olympic gold for a career Golden Slam, although he had a doubles gold from 2008). 2012 bronze medalist Argentinian
Juan Martín del Potro returned, as did quarterfinalists
Kei Nishikori of Japan (the fourth seed) and
Jo-Wilfried Tsonga of France (fifth seed). Barbados, Bosnia and Herzegovina, the Dominican Republic, Georgia, Lithuania, and Moldova each made their debut in the event. France made its 14th appearance, most among all nations, having missed only the 1904 event. ==Qualification==