Given name:
* Karl (name), a male given name of Germanic origin
* Carl (name), an English form of the above name
People:
* Carl (king of the Franks) (772–811), King of the Franks and Holy Roman Emperor
* Karl or Carl Marx (1818–1883), revolutionary socialist, philosopher, sociologist, economist, journalist and historian
* Carl Benz (1844–1929), German engineer, inventor and creator of the first practical automobile
* Carl Jung (1875–1961), Swiss psychiatrist and psychoanalyst who founded analytical psychology
* Sir Karl Popper (1902–1994), Austrian and later British philosopher, best known for his theory of falsifiability
* Carl Sagan (1934–1996), American astronomer, cosmologist, astrophysicist, astrobiologist, science communicator, and author
Places:
* Carl, Georgia, a town in Barrow County, Georgia, US
* Carl, West Virginia, an unincorporated community in Pocahontas County, West Virginia, US
* Karl, Kansas, an unincorporated community in Logan County, Kansas, US
* Carl Junction, Missouri, a city in Jasper County, Missouri, US
* Carl Creek Reservoir, a reservoir in Meade County, Kentucky, US
* Karl Island, a small island off Prince of Wales Island, Alaska, US
* Karl-Land, an island in Franz Josef Land, Russia