Gran Turismo 3: A-Spec is a 2001 sim racing video game developed by Polyphony Digital and published by Sony Computer Entertainment for the PlayStation 2. It is the third installment in the Gran Turismo series. During its demonstration at E3 2000 and E3 2001, the game was known under the working title Gran Turismo 2000. It is the bestselling PlayStation exclusive ever made.

With previous titles being developed for the original PlayStation, Gran Turismo 3 marked the series' first foray into the sixth generation of video game consoles. Originally slated for a 2000 release as a launch title for the PlayStation 2, the game's development primarily focused on taking advantage of the console's newfound hardware capabilities. While compromising on the number of available vehicles (180, as opposed to 650 in Gran Turismo 2), the game was a significant leap forward in terms of graphics, physics, sound design, car modelling, opponent AI, environments and technical performance.

Like its predecessors, the game released to critical acclaim and was a commercial success. It went on to become the best-selling game in the series to date, the best-selling PlayStation 2 exclusive, and the second best-selling PlayStation 2 game, having sold over 14 million copies since release. It is considered one of the greatest video games ever made. A landmark shift to the next generation of consoles, it is often cited as a turning point for the series and the sim racing genre as a whole.