Jay DeMarcus is an American bass guitarist, harmony vocalist, pianist, record producer and songwriter, who is a member of the country group Rascal Flatts.
- Born: April 26, 1971 (age 48), Columbus
- Spouse: Allison Alderson (2004-05-15 to present - Marriage)
- Aliases: DeMarcus, Jay, Stanley Wayne DeMarcus, Jr.
- Children: Dylan Jay DeMarcus, Madeline Leigh DeMarcus
- Genre: Country