‘Bois’ is the name of the family that held the manor in the 12th and 13th centuries.
The family name, also written de Bois, de Boys or de Bosco, distinguishes this parish, the most westerly of three Theydons. ‘Theydon’ is thought to mean a valley where thatching material grows. ‘Bois’ is pronounced ‘boyce’ or ‘boys’. The station opened in April 1865 as Theydon and took its full name that December.