2015 FIA World Endurance Championship

The 2015 FIA World Endurance Championship season was the fourth season of the FIA World Endurance Championship auto racing series, co-organized by the Fédération Internationale de l'Automobile (FIA) and the Automobile Club de l'Ouest (ACO). The series was open to Le Mans Prototypes and grand tourer-style racing cars meeting four ACO categories. World championship titles were awarded for Le Mans Prototypes drivers and for manufacturers in the LMP1 category, and several World Endurance Cups and Endurance Trophies were also awarded in all four categories. The season began at the Silverstone Circuit in April and ended at the Bahrain International Circuit in November after eight rounds, and included the 83rd running of the 24 Hours of Le Mans.

Porsche secured the World Manufacturers' Championship at the 6 Hours of Shanghai, beating Audi by eighty points. Porsche's Timo Bernhard, Mark Webber, and Brendon Hartley won the World Drivers' Championship in the final round of the season, ahead of Audi's André Lotterer, Benoît Tréluyer, and Marcel Fässler. Porsche teammates Marc Lieb, Romain Dumas, and Neel Jani were third in the championship standings. Bernhard, Webber, and Hartley won four consecutive races over the course of the season. Porsche also won the World Endurance Cup for GT Manufacturers in the final event, overcoming the lead held by Ferrari earlier in the season. Richard Lietz of Porsche won the World Endurance Cup for GT Drivers over three-time defending Cup winner Gianmaria Bruni and his teammate Toni Vilander.

Rebellion Racing and their drivers Mathias Beche and Nicolas Prost won the trophies for LMP1 class private entries despite not participating in the first two rounds of the championship. The championships were Rebellion's fourth and Beche and Prost's second consecutive trophy titles respectively. Roman Rusinov, Julien Canal, and Sam Bird of G-Drive Racing secured the LMP2 class trophies over the KCMG team. Porsche Team Manthey won the LMGTE Professional category trophy for teams over Ferrari representative AF Corse. The LMGTE Amateur category trophies were won by SMP Racing and their drivers Viktor Shaitar, Aleksey Basov, and Andrea Bertolini, ahead of AF Corse's LMGTE Am entry.

A provisional calendar was announced by the ACO at the 2014 6 Hours of Fuji and confirmed at the FIA World Motor Sport Council meeting in Doha shortly after. The schedule remained much the same as 2014, with the notable exception of the 6 Hours of São Paulo being replaced by the 6 Hours of Nürburgring. The planned construction of a new pit complex at the Autódromo José Carlos Pace precluded the event from returning in 2015. The Nürburgring round was the series' first visit to Germany and took place between the 24 Hours of Le Mans and 6 Hours of Circuit of the Americas, shortening the over three-month gap that was part of the 2014 schedule by three weeks.

The FIA unveiled an entry of 35 cars for the 2015 season on 5 February, divided into four categories: Le Mans Prototype 1 (LMP1) and 2 (LMP2), and Le Mans Grand Touring Endurance Professional (LMGTE Pro) and Amateur (LMGTE Am).

The LMP1-H and LMP1-L categories introduced in 2014 were merged once more into a single LMP1 category, allowing the privateer teams to again face the manufacturer teams. Nissan joined the LMP1 category as a manufacturer after supplying engines in LMP2 since the series' inception in 2012. The Nissan GT-R LM Nismo utilized a unique layout amongst the LMP1 field, with a front-engine design and a front-wheel drive powertrain. Nissan's drivers included FIA GT1 World Champion Michael Krumm, European Le Mans Series LMP2 champion Olivier Pla who moved from G-Drive Racing, and former Formula One driver Max Chilton. LMP2 veterans Harry Tincknell, Jann Mardenborough, and Alex Buncombe completed the team's full season line-up, while Lucas Ordóñez, Mark Shulzhitskiy, and defending Super GT champion Tsugio Matsuda drove the team's third entry for Le Mans.

Debutants in 2014, Porsche retained their line-up but added a third 919 Hybrid for Le Mans: current Force India Formula One driver Nico Hülkenberg joined Nick Tandy and Earl Bamber who were promoted from Porsche's LMGTE program.

With the retirement of 2013 World Endurance Drivers' champion Tom Kristensen, Audi promoted Oliver Jarvis to partner with Lucas di Grassi and Loïc Duval in an R18 e-tron quattro. The second Audi retained the same line-up which won the 2012 World Endurance Drivers' championship: Marcel Fässler, Benoît Tréluyer, and André Lotterer. René Rast moved from Audi's GT program to take Jarvis' vacated seat in the third Audi for Le Mans.