Ninja, Steel roller coaster in Six Flags Magic Mountain, California.

Ninja is a suspended steel roller coaster at Six Flags Magic Mountain in Valencia, California, built by Arrow Dynamics. Its trains hang beneath red track supported by white beams, and each seven-car train seats four riders per car. The ride reaches 55 mph (89 km/h), making it the joint-fastest suspended coaster in the world with Vortex at Canada's Wonderland.

Six Flags Magic Mountain announced Ninja on December 9, 1987, and the Arrow Dynamics suspended coaster opened on May 21, 1988, as the fifth of the ten original Arrow suspended coasters. Its station had served as the upper terminal of the Dragon tram until that ride closed in 1981; the tram's abandoned lower station stands near Jet Stream and Ninja's final brake run. In 2005 trains from Astroworld's XLR-8 were brought over, and the track was repainted red with white supports for 2007.

The station building is designed to resemble elements of Japanese architecture and displays several large renditions of classic Japanese woodblock prints of popular Kabuki actors of the Edo period, mostly by Tōshūsai Sharaku. The ride's name and setting place it in the Samurai Summit area of the park.

Riders must meet specific height requirements and secure all loose articles before boarding. The two-minute experience includes intense movements that may be uncomfortable for those sensitive to inversions and spinning motions.

The track includes two separate lift hills, with the second elevation near the end bringing trains back toward the station. This unusual setup creates two distinct phases of rapid descent within a single ride.