The bus went out of control about 8 a.m. on Highway 140 near Canton, about 40 miles north of Atlanta, while it was headed to Sequoyah High School and Dean Rusk Middle School.
Cherokee County sheriff's Sgt. Jay Baker said a preliminary analysis indicated the driver apparently overcorrected when the vehicle's right-side tires went off the pavement.
None of the students was thrown from the bus.
Witness William Lombardo said he and his workers at a company across the street saw the accident and rushed to help the students, keeping them from stepping on power lines that were downed by the crash.
"There was a loud noise, we heard a sound ... and you could see the bus going from left to right, clip a telephone pole, power lines start going off and the bus starts sliding under the power lines. The next thing you know it hits a pole and slides on its side," said Lombardo, 40, president of Risk Management Disaster Service.
One student was taken to Atlanta Medical Center by helicopter because the student had lost consciousness after the accident.
Although authorities initially said that youngster was in critical condition, Cherokee County Fire Department spokesman Tim Cavender said the student regained consciousness during the flight and officials decided the student's injuries were not life-threatening.
Ten other students were taken to North Fulton Hospital for treatment of neck and back injuries.
Remaining students were evaluated before being released to their parents, Cavender said.
Parents were told to gather at Sequoyah High School for more information. Cherokee County School District spokesman Brian Hightower did not immediately respond to a message seeking comment.