Altamont Pass (el. 1009 ft. / 308 m) is a mountain pass in Northern California, United States, located in the Diablo Range between Livermore in the Livermore Valley and Tracy in the San Joaquin Valley. The pass is similar in height to Pacheco Pass to the south.

The pass carries Interstate 580, heavily congested by Central Valley suburbanization, Altamont Pass Road which is the original alignment of US 50 before it was decertified, and two railroad right-of-ways (ROWs). Only one right-of-way is still in use: the old Western Pacific ROW, now owned by Union Pacific; it is today used for the Altamont Commuter Express, with service to Pleasanton, Fremont, and San Jose. The abandoned right-of-way was used by Southern Pacific, which is now part of Union Pacific.

The pass is known for the Altamont Pass Wind Farm, one of the earliest in the United States