Sonic Riders is a 2006 racing video game developed by Sonic Team and Now Production and published by Sega for the GameCube, PlayStation 2, and Xbox. In the game, the player controls characters from the Sonic the Hedgehog series on hoverboards and competes against opponents—either controlled by computers or other players—in races and battles. The game was released in February 2006 in Japan and North America, with a European release following the next month and a Windows version at the end of the year. A Game Boy Advance version developed by Backbone Entertainment was canceled.

The game was produced in commemoration of the Sonic series' 15th anniversary and was the first major Sonic racing game since Sonic R (1997) by Traveller's Tales. Sonic Team wanted to make their own game that was superior to any previous Sonic racing game. It was designed to appeal to fans of Sonic as well as extreme sports video games; the development team did not take inspiration from any prior games. Sonic Riders was also the last Sonic title produced with the involvement of franchise co-creator Yuji Naka, who acted as executive producer and left Sega shortly after its release.

Sonic Riders was released to mixed reviews from critics, but was a commercial success and was later re-released under the GameCube and PlayStation 2 bestseller lines. Reviewers mostly criticized the gameplay, controls, and overall design; while praise was directed at the game's visual style, soundtrack and sense of speed while racing; the Windows version also received criticism for its technical performance. Many deemed it a lackluster game—both within the Sonic franchise and the racing game medium—that did have its highlights but ultimately fell to its shortcomings. The game received two sequels, Sonic Riders: Zero Gravity (2008) and Sonic Free Riders (2010), which were developed and released to similar commercial success.

Sonic Riders is a racing game based around characters racing each other using devices known as "Extreme Gear", anti-gravity-equipped vehicles consisting of hoverboards, hover skates, and hoverbikes. Players compete to finish three laps around a racetrack before their opponents and complete the race in first place. Each race features up to eight characters competing. A key gameplay component is the air tank, displayed in the screen's lower right-hand corner. Air serves as the fuel for Extreme Gear, which is gradually depleted as the race continues. Characters can also perform a Boost, which will give them a sudden burst of speed at the cost of a significant amount of air. If a player boosts into an opponent, their character will attack and overtake them.

Air is also spent more quickly using techniques like drifting, which allows the player to round sharp turns easily, and building tension before a jump, which involves using the air to propel the player higher off the edge of ramps. If a player runs out of air, their character will start running on foot; this prevents them from boosting, attacking, cornering easily, or using charged jumps. Players can refill their air by using pit stops on the track, which force them to stay in place while their air meter recharges, or performing tricks when jumping off ramps or an opponent's slipstream, with higher-rated trick sequences restoring more air. Players can also collect rings scattered across the track; collecting a certain number of rings will cause their character to level up for the remainder of the race, increasing the strength of their abilities and extending their maximum air capacity.

Each character in Sonic Riders has different statistics, altering their performance slightly in races, though some characters are restricted from using certain types of Extreme Gear. Similar to Sonic Heroes, characters are divided into three classes, each with different abilities: Speed characters can grind on rails, Power characters can break certain objects, and Fly characters can fly through boost rings. Each race track features multiple shortcuts that can only be accessed by characters of a specific class. Players can spend the rings they acquire at the in-game shop to purchase new Extreme Gear, each of which possesses unique statistics and properties. The game includes eight unique areas, each with two track variants, for a total of 16 tracks. Only a few tracks are accessible from the start; the remainder are unlocked through game progression.

The game's Story Mode is divided into two campaigns, the events of which intersect with each other: the "Heroes" story, focused on Sonic, Tails, and Knuckles; and the "Babylon" story, focused on new characters Jet the Hawk, Wave the Swallow, and Storm the Albatross. In each campaign, players participate in consecutive races with predetermined characters and must take first place in each race to continue the story. Completing the Heroes campaign unlocks the Babylon campaign, which includes an epilogue in which the two stories converge. Additionally, players can compete in World Grand Prix mode, in which players race through five consecutive tracks and attempt to get the highest overall score. The game also features a Mission Mode with 100 missions to complete, each of which tasks the players with completing a specific objective within a time limit, such as collecting objects on the track or destroying a certain number of obstacles. Completing each mission awards players a bronze, silver, or gold medal based on the player's performance; by completing missions, players can unlock new characters and special Extreme Gear. Up to four players can compete in the game's single race and battle modes.

Sonic Riders features 16 playable characters, including guest characters from Nights into Dreams, Space Channel 5, and Super Monkey Ball.