Holmby Hills is a neighborhood in the district of Westwood in the westside of Los Angeles, California, United States.
The neighborhood was developed in the early twentieth century by the Janss Investment Company, which developed the rest of Westwood as well as other Los Angeles neighborhoods. With the expansion of Sunset Boulevard, Holmby Hills was split into northern and southern sections, each lying within a different community plan area designated by the City of Los Angeles: The portion south of Sunset Boulevard is the area north of Wilshire Boulevard and east of both Beverly Glen Boulevard and Comstock Avenue, and west of the Los Angeles Country Club; it is located within the Westwood Community Plan Area. The portion north of Sunset is the area east of Beverly Glen Boulevard and west of the city limits of Beverly Hills, with Greendale Drive and Brooklawn Drive as its northernmost streets; it is located within the Bel Air–Beverly Crest Community Plan Area, though it is historically distinct from the neighborhoods of both Bel Air and Beverly Crest.