Charlie Girling, of the 1st Aylesford Scouts, in Kent, collapsed on Sunday at Roihu 2016, near HÃ¤meenlinna.
The UK Scout Association said the on-site medical team and local paramedics "rendered immediate support but unfortunately were unable to save him".
Spokesman Simon Carter said it was in touch with the families of the children at the jamboree, which more than 16,000 people are attending.
"We will be working with the Finnish Scout movement and the relevant local authorities to establish the full details of this tragic incident," he added.
More than 2,800 scouts from more than 40 countries are attending the jamboree in the south of Finland.
Memorial services have been held at the event in tribute to Charlie.
Anna Munsterhjelm, chief scout in Finland, said: "The Guides and Scouts of Finland and Finnjamboree Roihu express their deepest condolences to the friends and family of the tragic medical situation that resulted in the death of a scout.
"The loss has moved thousands of people within and outside the camp.
"The camp has professional crisis counsellors that are making their utmost best that everybody has the support they require." (sic)
Charlie had been a Year 7 pupil at Maplesden Noakes School, in Maidstone.
Head teacher Jane Prideaux said staff were "deeply shocked and saddened" by his death.
"He'd been with us for just a year," she said.
"He was a lively lad, well-liked by his peers and teachers," she said.
Ms Prideaux added Charlie had been a "very hard working, very able student, with a great sense of humour".
"He was full of life, and wanted to get involved in things."

Images purporting to show an unnamed US warship were shown on television.
Iran's navy commander praised the operation for getting so close to a warship "to get such accurate footage of the combat units of foreign forces".
The US said an Iranian drone had flown over one of its carriers recently, but did not say if it was this incident.
It had not posed a risk to the USS Harry S Truman, but the move was "abnormal and unprofessional", Reuters news agency quoted a US navy spokeswoman as saying.
Nicole Schwegman said that incident had occurred on 12 January, which is the same day Iran briefly detained 10 US sailors who had entered Iranian territorial waters by mistake.
The report by Iran's state Irinn news channel did not say when the surveillance drone had made its flight except to say it was on the third day of a naval exercise.
The Associated Press news agency said this suggested it had happened on Friday, as Iran's naval drill began earlier this week.
An Iranian light submarine also closely participated in the surveillance operation, Iran's state-run Irna news agency reported.
Adm Habibollah Sayyari, Iran's navy chief, told state TV it was a sign of the "bravery, experience and the scientific capabilities of our drone operators".
International sanctions against Iran over its nuclear programme were lifted this month, somewhat easing its relations with the West.
But within a few days, the US had imposed new sanctions related to Iran's ballistic missile programme.
Iran said the sanctions, which prevent 11 entities and individuals linked to the programme from using the US banking system, had "no legal or moral legitimacy".
A 12-year-old scout has died at an international jamboree in Finland.
[NEXT_CONCEPT]
Iran flew an unarmed drone over a US aircraft carrier and took "precise" photographs during a naval drill in the Gulf, its state broadcaster said.