Orlando, Florida high school student Stormy Rich, 18, had been riding on a middle school bus to get to Umatilla High School.
On the bus, Rich was shocked by how some of the younger middle school girls were treating a student with mental disabilities.
Rich complained about the bullying to the bus driver, then to school officials, but says the adults took no action.
Rich told Fox 35 about the mean middle school bullies: "They would be mean to her, tell her she couldn't sit on certain spots on the bus. They were giving her food that they put in her mouth. I actually had to tell her to spit it out because she didn't understand."
"When the school didn't do anything, I told the girls, if the school didn't do anything, I was going to do something."
However, that warning got Rich into trouble with school officials, who have now banned her from riding the bus.
Amazingly, the school is standing behind its response, refused to give details and then complained how only one side of the story was being told.
Lake County Schools spokesman Christopher Patton said: "I can't comment about student discipline, you've got one side of the story. ... There are other parents that are involved in this."