The Santa Barbara Channel is that part of the Pacific Ocean which separates the mainland of California from the northern Channel Islands. It is generally south of the city of Santa Barbara, and west of the city of Ventura.

It trends east-west, is approximately 80 miles long and averages about thirty miles across, becoming narrowest at its easternmost extremity where Anacapa Island is less than twenty miles from the mainland.

The Santa Barbara Channel is considered a scenic location, with the islands visible from the mainland on clear days. The view is partly marred by oil platforms anchored in the channel.

Excursion boats cross the channel, taking visitors to watch whales and visit the islands. In the perpendicular (east-west) direction, huge cargo ships and tankers occupy a major shipping lane on their way to or from the ports of Los Angeles and Long Beach.

In 1969, the Santa Barbara Channel was the site of a major oil spill. Public outrage over the massive environmental damage inflicted by this spill was a major spur to the budding environmental movement.