The boy was questioned by police today over the alleged sex attack in Manchester.
The girl told cops she was grabbed from behind as she walked down the street before being dragged into the alley and raped on November 22.
The attack is alleged to have happened at 5pm in Chapel Street, near to the Horseshoe Pub in the Levenshulme area of the city.
Detective Inspector Dave Moores, of Greater Manchester Police's serious sexual offences unit, said: “This week we released an e-fit of a person we wished to speak to regarding this attack.
“I would like to thank the public for the response we have had.
“We have now arrested a 16-year-old boy. He is currently in custody being questioned.
“Our investigation is still ongoing however, so anyone who may have witnessed the incident or may have seen anything suspicious is asked to get in touch.
“There will still be an increased police presence in the community whilst the investigation continues to encourage those who have information to come and speak to us and reassure anyone with any concerns.”
Police offered to issue rape alarms and promised a permanent police presence to keep women safe following a spate of sex attacks in Manchester last year.
The attacks included the rape of another 12-year-old girl in Crowcroft Park, Levenshulme, on September 1.