Amanda L. Harris was charged with five counts of felony aggravated criminal sexual abuse.
An investigation determined that Harris had a "sexual relationship" with the boy "on at least five occasions," police said. The incidents took place during the month of January at the boy's home when his family was not there.
She was held in the Lake County Jail and ordered held in lieu of $30,000 bail.
Her next court date is Feb. 8.