Hidden Hills is a city and gated community in the Santa Monica Mountains region of Los Angeles County, California. It is located next to the cities of Los Angeles and Calabasas. The population was 1,725 at the 2020 census.

A gated community is a form of residential community or housing estate containing strictly controlled entrances for pedestrians, bicycles, and automobiles, and often characterized by a closed perimeter of walls and fences. Historically, cities have built defensive city walls and controlled gates to protect their inhabitants, and such fortifications have also separated quarters of some cities. Today, gated communities usually consist of small residential streets and include various shared amenities. For smaller communities, these amenities may include only a park or other common area. For larger communities, it may be possible for residents to stay within the community for most daily activities. Gated communities are a type of common interest development, but are distinct from intentional communities.