The 2015 FIM Moto3 World Championship was a part of the 67th F.I.M. Road Racing World Championship season. Álex Márquez was the reigning series champion but he did not defend his title as he joined the series' intermediate class, Moto2. Danny Kent became Great Britain's first Grand Prix motorcycle world champion since Barry Sheene in 1977, by winning the championship at the final race of the season in Valencia. Leopard Racing rider Kent started the season with wins at three of the first four races and his lowest finish in the first half of the season was fourth, leading the championship by 66 points at the mid-season break. He only visited the podium once in the second half of the season – a victory at Silverstone – as Enea Bastianini and latterly, Miguel Oliveira started to cut into his advantage. Oliveira trailed Kent by 110 points with 6 races remaining, but finished with 4 wins and 2 seconds in those races, and took the championship race to the final event as he became the closest challenger to Kent. Ultimately, Kent's ninth-place finish in Valencia gave him the championship by six points over Oliveira; both riders finished with six wins each, as Oliveira became Portugal's first motorcycle Grand Prix race-winner. Bastianini finished third in the championship, fifty-three points behind Kent; he won one race during the season, at Misano.

The 2015 FIM Moto2 World Championship was a part of the 67th F.I.M. Road Racing World Championship season. Marc VDS Racing Team rider Tito Rabat started the season as the defending riders' champion, having won his first championship title in 2014.