Crews from Beaconsfield, High Wycombe, Maidenhead, Slough and Reading (Caversham Road) attended with four officers following a report of a missing boy.
Two water rescue boats, supported by fire crews, were deployed on the water and bankside to search the area. Thames Valley Police were also supported by South Central Ambulance Service and HART, its Hazardous Area Response Team; the National Police Air Service; and Lowland Search and Rescue.
Following searches, the body of a boy was recovered from the river by divers. His next of kin has been informed.
Thames Valley Police say his death is being treated as unexplained and not suspicious, and a file will be prepared for the coroner.
Detective Inspector Mark Carolan, based at Reading police station, said: “Our thoughts remain with the boy’s family at this incredibly difficult time.
“I would like to thank the emergency services, local residents and the divers from Specialist Group International who assisted our officers in searching for the boy.”