Santa Barbara Island is a small island of the Channel Islands archipelago in California. It is located about 38 miles (61 km) off the Southern California coast from the Palos Verdes Peninsula, near Los Angeles in Ventura County, California.
With a total area of about 640 acres (2.6 km²) it is the smallest of the eight Channel Islands. It is the southern-most island in the Channel Islands National Park. The highest peak on the island is Signal Hill, at 634 feet (193 m).
While in Ventura County, the island is defined by the United States Census Bureau as Block 3012, Block Group 3, Census Tract 29.10 of Santa Barbara County, California. According to the 2000 census the island is uninhabited and has a total land area of 2.625 km² (1.0136 sq mi).