Forza is the Xbox racing series that includes the open-world Forza Horizon spin-off.
The Forza franchise began with Forza Motorsport in 2005. The Motorsport games focus on circuit racing and vehicle simulation, while Forza Horizon places driving in large open environments inspired by real-world locations and festivals.
Playground Games developed the first Forza Horizon, which launched in 2012 for Xbox 360. Turn 10 Studios created the Motorsport line and worked with Playground Games on the broader franchise relationship under Microsoft’s Xbox publishing structure.
Project Gotham Racing is an easy alternative to confuse with Forza because it was also a major Xbox racing series. However, Project Gotham Racing was developed by Bizarre Creations and did not provide the Horizon subseries. Forza is the umbrella name covering both Motorsport and Horizon.