Catherine Ariemma says the costumes were part of a film re-enactment project she assigned to U.S. history students at Lumpkin County High School near Atlanta, the Atlanta Journal-Constitution reports.
Ariemma, a six-year veteran with the school system, told the newspaper she may have made a mistake allowing the filming to be done on campus.
The teacher said she walked four students dressed as Klansmen through the cafeteria not realizing that other students were having lunch at the time.
Senior Cody Rider said he was offended when he saw people dressed in white hoods and sheets walking through the school cafeteria.
Ariemma has been placed on paid suspension.
"Good common sense should have told her this was not a good idea," the Rev. Markel Hutchins told a community meeting Monday night.