Calabasas is a city in Los Angeles County, California, in the western United States. As of the 2005 census, the city population was 23,123. The city was formally incorporated in 1991. Many parts of Calabasas are mountains or hills, which have spectacular views of the San Fernando Valley. Many of the neighborhoods in Calabasas are gated communities of McMansions.

The city is located at the southwestern edge of the San Fernando Valley and comprises a portion of the Santa Monica Mountains. It is bordered by the Woodland Hills area of Los Angeles to the northeast, Topanga to the southeast, Malibu to the south, Agoura Hills to the west, and Hidden Hills to the north. The historic El Camino Real runs east-west through Calabasas as U.S. Route 101.

Calabasas funds its own public transportation in the form of shuttle and trolley service (as opposed to using the default Los Angeles County bus service), funds its own library (as opposed to using the County library system), runs its own tennis and swimming center , has a protected and maintained historical district, has its own television channel called "The Calabasas Channel", and has four car dealerships along Calabasas Road. While Calabasas is often times considered similar to its neighboring two cities to the west (Agoura Hills and Westlake Village, which is a trio that can be compared to the Burbank-Glendale-Pasadena area) because of similar demographics, size (physically and population, save Westlake), geography, and low-density general plans, Calabasas is unique from these two for the above things as the two other cities have none of the above features.

In February 2006, Calabasas placed a ban on smoking in nearly all public places, including sidewalks, parking lots, patios, and even outdoor balconies in apartment complexes if they were near common areas , making it the city with the strictest anti-smoking laws in the United States. Under the new laws, smoking outside in the city is restricted to selected "smoker outposts." Smoking in undesignated areas under the new law could earn smokers fines of up to $500. The ban went into effect in March 2006, garnering much local and national media attention. The full text of the ordinance may be found at Calabasas' official website on the issue.