Barnet may refer to:
- Chipping Barnet or High Barnet, commonly known as Barnet, one of three focal towns of the borough below.
- East Barnet, a district of the borough below; ancient parish.
- New Barnet, a district of the borough below.
- Friern Barnet, a district of the borough below.
- Administrative units
- London Borough of Barnet, in Greater London, England
- Barnet (UK Parliament constituency) (1945–1974)
- Chipping Barnet (UK Parliament constituency) (since 1974)
- Historic units
- Barnet Urban District (1863–1965) in Hertfordshire
- East Barnet Urban District neighbour with same status/lifetime as above
- Barnet Rural District, former name (1894–1941) of Elstree Rural District
- Barnet, Vermont, United States, a New England town
- Barnet (CDP), Vermont, village in the town
- Barnet Run, a stream in West Virginia, United States
- Barnet, British Columbia, Canada, a settlement now part of the city of Burnaby
- Battle of Barnet, in the Wars of the Roses in 15th century England
- Barnet F.C., a football club in London
- Barnet, Danish title of the 1940 Danish film The Child
- "Barnet", rhyming slang for "hair" (from "Barnet Fair")