John Mercer
John Mercer is the name of:
- Captain John Mercer, colonial Virginia militiaman killed at the Battle of Great Cacapon
- John Mercer (colonial lawyer), colonial Virginia lawyer
- John Francis Mercer, American Governor of Maryland, 1801–1803, son of the Virginia lawyer
- John H. Mercer, American Ohio State University glaciologist
- John Mercer (scientist), British textile chemist
- John Mercer (Australian pastoralist), Australian landowner, pastoralist and politician in colonial Victoria
- John Mercer (baseball), American Major League Baseball first baseman
- John Mercer (archaeologist), British archaeologist and author
- John Mercer (American politician), American legislator in the state of Montana
- John Mercer (photojournalist), New Zealand photographer and photojournalist
- Johnny Mercer, American songwriter
- Johnny Mercer (politician), British politician
- Jack Mercer, American animator and voice actor
- Jack Mercer (cricketer), British cricketer for Glamorgan
- Jack Mercer (baseball), Major League Baseball pitcher