Lennox is a census-designated place (CDP) in the South Bay region of Los Angeles County, California, United States. The population was 22,753 at the 2010 census, down from 22,950 at the 2000 census.

The South Bay is a region of the Los Angeles metropolitan area, located in the southwest corner of Los Angeles County. The name stems from its geographic location stretching along the southern shore of Santa Monica Bay. The South Bay contains sixteen cities plus portions of the City of Los Angeles and unincorporated portions of the county. The area is bounded by the Pacific Ocean on the south and west and generally by the City of Los Angeles on the north and east.