Authorities say the girl had claimed she was walking across the street from the school when a man told her he had been sent to pick her up.
She said she had asked the man a question he was unable to answer and then stabbed him in the leg with a pencil before getting away.
Investigators say detectives and school administrators tried to find people who witnessed the alleged incident.
When officers went to re-interview the girl for more information, she said she had made up the incident as a joke, police said.
Police say she is not currently facing legal trouble, however, she may face disciplinary action at school.