The Kawasaki Ninja motorcycle is a series of sport bike and off-road bike models made by the Japanese motorcycle manufacturer Kawasaki. The most popular models are the Ninja 250R, Ninja ZX-6R, Ninja ZX-10R, and Ninja H2. The Ninja 250R is a small lightweight bike suitable for beginner riders, while the larger Ninja models are designed for more experienced riders looking for higher performance.