The Los Angeles Westside is an urban region in western Los Angeles County, California, United States. It has no official definition, but, according to the Los Angeles Times, it comprises 101.28 square miles (262 km²), encompassing 18 districts in the city of Los Angeles and two unincorporated neighborhoods, plus the cities of Beverly Hills, Culver City, and Santa Monica.

Many of the major educational, retail, cultural, and recreational attractions of Greater Los Angeles are located in this area, as is a large portion of the entertainment industry. Century City is a major business hub of the Westside, containing many major production corporations, talent agencies, and entertainment law firms. Culver City houses several film studios and commercial effects houses. Santa Monica, Venice, Beverly Hills, and new developments near LAX are also important entertainment industry centers.

The Westside rivals downtown Los Angeles for the number of people commuting to it from other areas, in particular the San Fernando Valley to the north and the South Bay to the south.

Los Angeles (ⁱ/lɒs ˈændʒələs/ loss-AN-jə-ləs; Spanish: [los ˈaŋxeles], which is written Los Ángeles; British pronounciation /lɒs ˈændʒəliːz/ loss-AN-jə-leez) with a population at the 2010 United States Census of 3,792,621, is the most populous city in the state of California, and the second most populous in the United States, after New York City. It has an area of 468.67 square miles (1,213.8 km²), and is located in Southern California. Often known by its initials L.A., the city is the focal point of the larger Los Angeles-Long Beach-Santa Ana metropolitan statistical area and Greater Los Angeles Area region, which contain 12,828,837 and nearly 18 million people respectively as of 2010, making it one of the most populous metropolitan areas in the world and the second largest in the United States. Los Angeles is also the seat of Los Angeles County, the most populated and one of the most ethnically diverse counties in the United States, while the entire Los Angeles area itself has been recognized as the most diverse of the nation's largest cities. The city's inhabitants are referred to as "Angelenos".