Dean Berta Vinales died following a crash in Race 1 of the Motul Spanish Round of the FIM Supersport 300 World Championship, MotoGP announced on Saturday.
The Spanish rider was involved in a multi-rider accident at the Circuit of Jerez-Angel Nieto, Spain, and the race was immediately red flagged.
Medical vehicles quickly arrived at the site but despite their best efforts, it was announced that 15-year-old succumbed to his injuries.
Following the incident, the remainder action at Jerez has been cancelled.
The FIM, Dorna Sports and the Circuit of Jerez-Angel Nieto extended their deepest condolences from the official website of MotoGP.
Berta Vinales, cousin of MotoGP rider Maverick Vinales, was enjoying good form in his rookie season in the FIM Supersport 300 World Championship.
He claimed a best of fourth place at Magny-Cours, France, in Race 2, backing it up with sixth in Barcelona-Catalonia Race 2 and having set the fastest lap in Race 1.