The driver, known to students as 'Ms Pat' called the girl a 'cry baby,' before inviting other students to taunt the upset child.
"Ready?" she says. "Cry, cry, cry!"
As the girl continues to sob, Ms Pat can be heard mocking her, saying, "I want my mama."
The footage appears to be from a security camera on the bus, which was carrying children to school in Texas, US.
A mother of one of the students on the bus became visibly upset when she was shown the video,
"If you can't bully at school, why are they allowing it on the bus?" Monna Perez said to KSAT.
While another parent has said that following the incident her son no longer wants to ride the school bus and has asked her to drive him to school instead.
According to the School District Superintendent Dr. Sherri Bays, the driver of the bus has been disciplined, but she has not been fired.
"It's definitely not appropriate," Bays said after watching the footage. "I think she's acting very childish and immature."
"I expect that person to learn from that mistake and we will continue to monitor that."
More on Parentdish