Ottawa High School will be a costume-free zone on Halloween.

Students are being asked to not wear costumes to school Wednesday, Ryan Cobbs, Ottawa High School principal, said in an email Tuesday. Allowing students to wear costumes to school has caused “major disruptions” in the past, Cobbs said.

“We feel that by not allowing this to happen we can better ensure a quality learning process,” Cobbs said.

Parents were asked to remind children not to wear costumes to school Wednesday. If a student shows up to school in costume, school officials plan to contact the student’s parent and send them home to change clothes.