Nick Allen—the main character, an inventive fifth grader at Lincoln Elementary School.
Miss Deaver—Nick's third-grade teacher, a new educator.
Manny—the custodian at Lincoln.
Mrs. Avery—Nick's hawk-nosed third-grade teacher.
Janet Fisk—Nick's friend, and a co-conspirator in the blackbird noises in fourth grade.
Mrs. Granger—Nick's nemesis, and the fifth-grade language arts teacher.
Mrs. Allen—Nick's mom.
James Allen—Nick's older brother. He is in college when Nick is in fifth grade.
John, Pete, Chris, and Dave—other fifth graders who Nick gets to spread the term "frindle."
Mrs. Margaret Chatham—principal of Lincoln Elementary, she is a large, firm woman.
Tom Allen—Nick's father.
Judy Morgan—reporter for The Westfield Gazette.
Ted Bell—sells ads for The Westfield Gazette. He passes the frindle story to Judy.
Mrs. Freed—the Lincoln Elementary School secretary.
Bud Lawrence—a local tycoon who helps spread the term "frindle."
Alice Lunderson—works for a television station in Betherly, a town near Westfield.