Hanger Wood is an ancient woodland and Site of Special Scientific Interest (SSSI) in the parish of Stagsden, Bedfordshire, in the United Kingdom. Situated approximately 2⁄3 mile (1.1 km) east of the village of Stagsden, the 24.12 hectares woodland was declared a SSSI in 1988, being described by Natural England as "one of the best remaining examples of wet ash-maple woodland in Bedfordshire". The name "Hanger" comes from Old English/Anglo-Saxon term for "wood on a hill" or "wooded hill", applied to Hanger Wood due to its situation on a northwest-facing slope of a narrow ridge. Commenting on the wood's character, A. Simco said in 1984 that "It has been strongly influenced by the geology and topography of the area, particularly by the south-west/north-east boulder clay ridge along which the parish boundary runs."