Showalter is a surname common in the United States, and is possibly an anglicized variant of the German Schulter ("shoulder"). It may refer to:
- Anthony Johnson Showalter (1858–1924), an American gospel music composer, teacher and publisher
- Buck Showalter (b. 1956), a former professional baseball player and current manager of the Baltimore Orioles
- Dennis Showalter, American historian
- Don Showalter, a professor and former chairman of the Department of Chemistry at the University of Wisconsin–Stevens Point
- Elaine Showalter (b. 1941), an American literary critic, feminist, and writer on cultural and social issues
- Gena Showalter (b. 1975), an American Author in the genres of Contemporary Romance, Paranormal Romance, and Young Adult
- Jackson Showalter (1860–1935), a 5-time U.S. Chess Champion
- Joseph Baltzell Showalter (1851–1932), a Republican member of the U.S. House of Representatives from Pennsylvania
- Mark R. Showalter (b. 1957), an American astronomer
- Max Showalter (1917–2000), an American film, television and stage actor
- Michael Showalter (b. 1970), an American actor, writer, and director and part of the sketch comedy trio Stella
- William Showalter