The men's (outdoor) singles was one of six lawn tennis events on the Tennis at the 1908 Summer Olympics programme. The tournament was played on grass courts at the All England Lawn Tennis and Croquet Club. There were 31 competitors from 9 nations. Nations could enter up to 12 players. The event was won by Major Ritchie of Great Britain, the nation's third victory in four Games. Otto Froitzheim earned Germany's first medal in the event with his silver. Another Briton, Wilberforce Eaves, took bronze.

Tennis was part of the Summer Olympic Games program from the inaugural 1896 Summer Olympics, but was dropped after the 1924 Summer Olympics due to disputes between the International Lawn Tennis Federation and the International Olympic Committee over how to define amateur players. After two appearances as a demonstration sport in 1968 and 1984, it returned as a full medal sport at the 1988 Summer Olympics open for all players regardless of their age and status and has been played at every summer Games since then.