California Jam was a rock music festival concert held at the Ontario Motor Speedway in Ontario, California on April 6, 1974. It attracted over 200,000 fans, and was one of the last of the original wave of rock festivals, as well as one of the most well-executed and financially successful, and presaged the era of media consolidation and the corporatization of the rock music industry.

Unlike other rock festivals such as Woodstock, the concert was never released as a film or sound recording, however several portions of it were broadcast live on the ABC television network, which was also a sponsor of the show. The audio portion of the show was also broadcast in stereo on FM radio stations, an early example of simulcasting.

Acts that performed at the festival included:

• Black Sabbath
• Black Oak Arkansas
• The Eagles
• Deep Purple
• Emerson, Lake and Palmer
• Earth, Wind and Fire
• Rare Earth
• Seals & Crofts

A sequel concert, California Jam II, was held in 1978.