The 2025 Supersport 300 World Championship was a part of the 38th season of the Superbike World Championship. It was the final edition of the championship, with a new category set to replace it in 2026. The championship consisted of 16 races across 8 venues.
Beñat Fernández won the championship title at the final round in Jerez.
The provisional 2025 season calendar was announced on 11 October 2024.