Fire crews were at the scene within minutes after thick plumes of smoke were spotted billowing across the town.
A joint venture between Lincoln Property Company and MGT Investment Management is developing the £750m Station Hill mixed-use scheme.
Site sources told the Enquirer the fire was on the phase one residential part of the scheme were JRL Midgard is main contractor.
Royal Berkshire Fire and Rescue Service said: “At 3:42pm on Friday, 07 July, we received reports of a fire in a high-rise construction site on Garrard Street in Reading.
“Royal Berkshire Fire and Rescue Service crews were sent to the scene. An Aerial Ladder Platform, Incident Command Unit and five Officers were also sent to the scene alongside crews from Oxfordshire Fire and Rescue Service.
“Firefighters were at the scene of the incident within 90 seconds and rapidly intervened to prevent the spread of a fire in a high-rise construction site and ensured that all persons onsite were safe and accounted for.
“Using a drone from Thames Valley Police and an external lift at the site, firefighters were able to quickly locate and tackle a fire on the twelfth and thirteenth floors of the building. Firefighters equipped with breathing apparatus then used a jet to extinguish the fire.”