Thebes is a village in Alexander County, Illinois, United States. The population was 478 at the 2000 census. It is part of the Cape Girardeau–Jackson, MO-IL Metropolitan Statistical Area.
Thebes is located at 37°13′9″N 89°27′25″W / 37.21917°N 89.45694°W / 37.21917; -89.45694 (37.219177, -89.456915).
According to the United States Census Bureau, the village has a total area of 2.3 square miles (6.0 km²), of which, 1.8 square miles (4.7 km²) of it is land and 0.5 square miles (1.3 km²) of it (22.08%) is water.