Caitlin White, 15, died in Craigavon Hospital after being found unconscious near Portadown's Corcrain estate on Saturday evening. The exact cause of death is not yet known.
Her funeral is set to take place at the Church of the Assumption in Newry, County Down at 12:00 BST.
The boy was the third person arrested in connection with the death.
A 17-year-old boy and a 19-year-old man were arrested on Monday.
They were released on bail pending further inquiries on Tuesday.
Police have said a possible link to drugs is one line of inquiry into the Craigavon Senior High School pupil's death.
A 15-year-old boy arrested after the death of a Portadown schoolgirl has been released on bail.