A 13-year-old boy was arrested after he set a girl’s hair on fire at their Long Island middle school Friday, cops said.

The fire was quickly extinguished at about 8 a.m. at the William Paca Middle School in Shirley, Suffolk County cops said.

The 14-year-old girl declined medical attention and was released to her parents. The boy, who was not identified, is being charged as a juvenile.

In a statement, the school said it was working with cops to help prosecute the teen to the “fullest extent of the law.”

“The William Floyd School District has zero tolerance for this type of behavior,” the statement read.