Emergency service officials said the 14-year-old, from Gore, had previously been in the nearby multi-storey Meridian car park building with other youngsters.
Another youngster had been "skylarking", and had apparently thrown the teenager's cellphone on to the bank roof.
The teenager had jumped across a gap between the buildings and down about 1.5m to retrieve the phone but could not return to the higher building.
A security guard apparently contacted the Fire Service and firefighters were alerted at 2.42pm.
An "aerial appliance", equipped with a rescue cage, and with Senior Firefighters Ant O'Neill and Greg Wilson aboard, lifted the teenager to safety within a few minutes, officials said.
Acting Senior Sergeant Chris McLellan, of Dunedin, said no action was being taken by police over the incident.
