Marc Márquez started the season as the defending riders' champion, having won his second consecutive title in 2014. He had been undefeated in championships throughout his MotoGP career and won a record breaking 13 wins in a season.
Valentino Rossi led the championship for almost the entire season as he chased a tenth world title, but ultimately, the honours went to his
Yamaha teammate
Jorge Lorenzo, who took his third MotoGP title and a fifth world title overall. Lorenzo started the season quietly with three finishes off the podium, Rossi stayed upright but Márquez was unable to rejoin the race, with Rossi calling Márquez voicing his displeasure in the press conference after the race, beginning an estrangement between the two riders that would impact the season and Lorenzo's eventual championship. Thereafter, Lorenzo took four successive wins for the first time in his career to bring himself back into the championship race, before Rossi won at
Assen. Lorenzo did not win again until
Brno, taking the championship lead on countback, but ceded it back to Rossi, when he won at
Silverstone. Lorenzo crashed out at
Misano, Rossi and Márquez again collided at Assen on the final lap; Rossi rejoined the circuit through the gravel and went on to win the race, while race direction deemed the incident as a racing incident. The
Australian Grand Prix was won by Márquez, with Lorenzo second, Ducati's
Andrea Iannone finishing third and Rossi fourth, in a race considered to be one of the greatest in MotoGP's history. There were more than 50 overtakes made between these four riders throughout the race, with 13 lead changes and Márquez setting the fastest lap on the final lap to ensure victory. Despite the incredible response from fans, Rossi was unhappy with how the race unfolded and, in the following pre-event press conference at
Malaysia one week later, accused Marquez of helping Lorenzo in his title aspirations (a claim which Márquez refuted). This led leading up to one of the most infamous races in the sport's history one week later. The
Malaysian race was originally at risk of cancellation due to smoke from fires in Indonesia impacting the track, but ultimately went ahead. After a series of 18 overtakes and exchanges of positions between Rossi and Marquez while battling for third place, the two riders came together for their third collision of the season during lap seven. Rossi made a move on Márquez at Turn 14, pushing him to the outside of the circuit. The riders made contact and Márquez fell from his bike. Although he was able to remount his bike, Marquez was forced to pit and retire from the race. Rossi was able to maintain his position and finished the race in third place, with Márquez's
Repsol Honda teammate
Dani Pedrosa taking the win and Lorenzo finishing second. Despite Rossi appealing the penalty to the
Court of Arbitration for Sport, the penalty was upheld and he was forced to start the final race of the season, in
Valencia, from the back of the grid. Although Rossi voiced his regret at the move on Márquez, he did not apologise for the incident occurring. Race winner Pedrosa criticised Rossi's reaction to the incident, calling his response contradictory to previous comments made by Rossi on racing incidents, and Lorenzo made statements deeming the penalty "inadequate". Lorenzo submitted a statement against Rossi's appeal of the penalty but later apologised for his actions on the podium. Márquez defended his riding style in Malaysia, stating his disappointment towards both his rival's actions on the track and subsequent comments made to race direction. In the four races leading up to the final round in Valencia, Rossi had finished ahead of Lorenzo only once, with the points gap between the two teammates closing from 23 after
San Marino to just seven going into the final round. It was the first time in nine years that the championship would be determined in the final round, following
Nicky Hayden's victory over Rossi in
2006. At the final race, Rossi recovered from the back of the grid to finish fourth, while Lorenzo took his seventh win of the season to secure the world title by five points; the first time that Lorenzo had held a points lead all season. Rossi finished second place in the championship with a total of five wins and 15 podiums over the season, 83 points ahead of Marquez who had matched Rossi on wins but suffered six retirements. The only other rider to win a race during the season was Márquez's teammate Pedrosa, who took two wins in the closing four races, at
Motegi and
Sepang, after missing three races at the start of the season to undergo arm-pump surgery.
Other championship standings The combined eleven wins and 27 podiums by Rossi and Lorenzo were enough to secure both the team's title for Movistar Yamaha, more than 200 points ahead of runner up Repsol Honda, and the manufacturers' title for Yamaha, 52 points ahead of Honda. Amongst the class of rookies,
Suzuki rider
Maverick Viñales took the IRTA Cup, finishing in twelfth place overall, while
Héctor Barberá of
Avintia Racing was the best-placed Open class rider, in fifteenth. ==Calendar==