Ronald Alan Olson, 24, worked at Wendell Middle School.
A Wake County Public School System spokesperson said Olson stepped down from his position the day before his arrest.
According to an arrest warrant filed by the Wake County Sheriff's Office, the alleged sex offense took place with one child under the age of 13 between August 3 and October 24.
Olson had a court appearance Wednesday. Bond was set at $600,000.