Test Drive Unlimited is a 2006 racing video game developed by Eden Games and published by Atari for Xbox 360 and Microsoft Windows. Atari Melbourne House developed the PlayStation 2 and PlayStation Portable versions. Being the eighteenth entry in the Test Drive series, Unlimited serves as a reboot of the franchise, discarding the continuity of the previous games. The game features over 125 licensed sports cars and motorcycles and the terrain is modeled after the Hawaiian island of Oʻahu that features over 1,000 miles (1,600 km) of roads and highways.

It was followed by a sequel, Test Drive Unlimited 2, in 2011. A third game and soft reboot, Test Drive Unlimited Solar Crown, was released in 2024.

In the online world of Test Drive Unlimited, players are able to drive both on-road and off-road in free-roam mode, challenging other players in real-time anywhere on the drivable map. It is also possible to drive on small islands outside of the main island. The Xbox 360 version has supported steering wheel controllers since launch. Following the third free update, Test Drive Unlimited supports force feedback wheel controllers such as Microsoft's Xbox 360 Wireless Racing Wheel.

The roads are modeled after satellite images of the island of Oʻahu. There is a spectrum of different terrains including rain forests, mountains, sandy beaches and urbanized areas (featuring the city of Honolulu).

The game begins by purchasing a car and a house. The player is then free to explore the island; as this happens, key locations on the map are revealed.

The multiplayer component (branded as M.O.O.R. or Massively Open Online Racing) works as an extra layer on top of the single-player game: all activities available in single-player are also available in multiplayer. On Xbox 360, Eden Games was allowed to add unique features to the Xboxlive in order to bring a new seamless Online experience.

The following challenges are also available in multiplayer only:

Custom services, added to the XboxLive by Eden Games: