In the Metal Gear franchise, Solid Snake's real name has never been revealed

Explanation

It was revealed at the end of the original "Metal Gear Solid" (1998) that his real name is David, which is a reference to David Bowman from "2001: A Space Odyssey" and to Dave Forrest from Hideo Kojima's "Policenauts". Otacon's real name, Hal Emmerich, completes the pair as a reference to HAL 9000.