Chattanooga firefighters responded to a small fire at Calvin Donaldson Elementary School around 11:30 a.m. on Tuesday.
A fire investigator says a boy in the fourth grade took his shirt off in the bathroom and set it on fire.
The fire was quickly extinguished by the principal and her staff, but the entire school was evacuated as a precaution.
No one was injured.
There was no damage to the school.
The fire investigator said the student was taken to Children's Hospital at Erlanger for an evaluation.