The Infiniti FX is a mid-size Crossover SUV produced by the Nissan-owned Infiniti luxury vehicle brand since the 2003 model year. The FX replaced the QX4 as Infiniti's mid-size luxury-type SUV, despite being larger than its predecessor. It was released at the same time as its competitors, the Porsche Cayenne, Volvo XC90, and Volkswagen Touareg. It shares the same FM platform as the rear-wheel drive Nissan 350Z, whereas the similarly sized Nissan Murano is based on the front-wheel drive Nissan Altima platform.

The Infiniti FX is not sold in Japan.

In creating the FX, its designers sought what they called a "cool fusion" – the blending of a substantial, SUV lower body with the sleek, elegant upper body more reminiscent of a classic sports car or sports GT. [1] In addition, they sought to combine sports-car performance with SUV functionality. The FX is a unique combination of aggressive styling, performance and luxury car comfort. The FX was based on the notion of a "Bionic Cheetah," with advanced technology employed to create a premium crossover SUV.[2] The FX is now in its second generation with the 2009 FX35 and FX50.