Stevenson Ranch, California (in the 91381 ZIP Code) is a Los Angeles County, USA, community in the Santa Clarita Valley a few miles south of Six Flags Magic Mountain amusement park. It is a growing community north of the San Fernando Valley and Greater Los Angeles Area. It has many new suburban one- and two-story houses in new developments. The area encompasses about 4,000 acres (16 km²). About 1,000 acres (4 km²) are set aside as parks, recreation areas and open space.

The newest community in Santa Clarita Valley, Stevenson Ranch is set in the foothills of the Santa Susana Mountains and lies west of the I-5 freeway. This area backs up to the historic, oil-mining town of Mentryville, founded in 1875. Stevenson Ranch consists of 4,001 acres (16 km²) of rolling hills offering a variety of home types. A planned community, it was approved by the county in 1987. The Valencia Marketplace and Stevenson Ranch Shopping Center are popular shopping areas in the community. The elementary, junior high, and high school are award winning schools.

The names of many streets located in Stevenson Ranch are those of famous authors. However, the street known as "Thackery Lane" is actually an as of yet uncorrected misspelling that refers to the 19th century English novelist, William Makepeace Thackeray

In television

The main entrance to Stevenson Ranch (as seen in the photo) is featured in the television show Weeds, in which the sign has been altered to read Agrestic (or Majestic in later seasons).