Whippendell Wood (or Whippendell Woods) is an ancient woodland on the edges of Watford, England, covering an area of 165.3 acres (66.9 ha). It is owned and managed by Watford Borough Council. It is a Site of Special Scientific Interest, and has held this status since 1954. Its present name comes from the Anglo-Saxon name "Wippa denu", meaning "Wippa's valley".