Fifteen-year-old Dean Berta Vinales died following a crash in the Supersport 300 support race of the World Superbike Championship in Jerez, organisers said on Saturday.
The race was 11 laps old when Spaniard Vinales crashed along with three other riders at turn two, forcing the director to red flag the race.
"After a serious incident during WorldSSP300 Race 1, Dean Berta Vinales has sadly succumbed to injuries," World Superbike said in a statement.
"The rider suffered severe head and thoracic injuries. Medical vehicles arrived at the site immediately and, the rider was attended to on track, in the ambulance and at the circuit Medical Centre.
"Despite the best efforts of the circuit medical staff, the Medical Centre has announced that Berta Vinales has sadly succumbed to his injuries."
The race and the remainder of Saturday's action were cancelled.
Vinales is the cousin of MotoGP rider Maverick Vinales and, he rode for the Vinales Racing Team.
"We're devastated by the tragic loss of @DeanBerta21 following a crash in #WorldSSP300 Race 1 today," MotoGP wrote on Twitter.
"Sending all our love and strength to Maverick Vinales and Dean's entire family, his team and loved ones."
Six-times MotoGP champion Marc Marquez wrote: "Rest in peace Dean. All my support to family and friends."
- IND vs AUS Live Score, 3rd T20I: Australia wins toss, elects to bowl against India; Avesh replaces Mukesh in India playing XI
- Indian sports news wrap, November 28
- T20 World Cup Africa qualifier points table: Namibia qualifies for T20 WC 2024; Uganda, Zimbabwe, Kenya battle for last spot
- Returning officer likely to take decision of WFI poll date on Wednesday: Ad hoc panel’s Bajwa
- IND vs AUS 3rd T20I Dream11 Prediction: India vs Australia predicted playing XI, line-ups, full squads