Jmyha Rickman had a meltdown at Lovejoy Elementary School in Alton, Illinois, U.S., because she had asked to go to the toilet several times but was ignored.
When staff failed to calm her down they called the police. An officer turned up and put the girl's hands behind her back in handcuffs before putting her in a police car and carting her off to the station.
It's understood that Jmyha had had tantrums before but this time the staff couldn't handle her.
The girl's guardian, Nehemiah Keeton, told news station KMOV-TV: "Her eyes were swollen from her crying and her wrists had welts on them and they cuffed her feet too."
Defending the school's actions, Kristie Baumgartner, assistant superintendent of the Alton School District, said that if a student is at risk of harming themselves or others, police would be called if the child's parent or guardian refuses to pick them up.
Alton police said Jmyha was placed in a juvenile detention room and was supervised the whole time.
The department also claimed that the girl was out of control and tearing up two classrooms - and the officer believes he did the right thing.